Sunday, March 8, 2015

FS-T6 firmware upgrade

As we are working on FS-T6 custom FW (called AR-T6) we are trying to provide an easy path for early adaptors. Here is how to program the AR-T6 firmware  into your Tx or revert to the original. Both without opening the case.

What is needed:
- stm32flash utility (can be build on linux and windows) or a STM loader demonstrator
- compiled ar-t6.bin or original fs-t6.bin fw
- serial port or usb-to-serial adapter
- some means to connect adapter's leads to the port on FS-T6
- some knowledge of cmd line on linux

BLACK - GND to the S-Video ring
WHITE - PC Rx to T6's Tx
GREEN - PC Tx to T6's Rx
(see: student cable for connections)

Note that to get a good grounding I had to bend the pin of black ground wire and wedged it into the space.
Also note that the connection is potentially very flaky and may soft-brick your Tx if interrupted in the middle (recovery possible but only with an SWD cable). A safer way would be to use a CT6B cable or to make a custom cable from an S-Video described here)


check connection:

~/stm32flash$ sudo ./stm32flash /dev/ttyUSB0
stm32flash 0.4

Interface serial_posix: 57600 8E1
Version      : 0x22
Option 1     : 0x00
Option 2     : 0x00
Device ID    : 0x0420 (Medium-density VL)
- RAM        : 8KiB  (512b reserved by bootloader)
- Flash      : 128KiB (sector size: 4x1024)
- Option RAM : 16b
- System RAM : 2KiB

To program custom fw:
~/stm32flash$ sudo ./stm32flash -w ar-t6.bin -v /dev/ttyUSB0
stm32flash 0.4

Using Parser : Raw BINARY
Interface serial_posix: 57600 8E1
Version      : 0x22
Option 1     : 0x00
Option 2     : 0x00
Device ID    : 0x0420 (Medium-density VL)
- RAM        : 8KiB  (512b reserved by bootloader)
- Flash      : 128KiB (sector size: 4x1024)
- Option RAM : 16b
- System RAM : 2KiB
Write to memory
Erasing memory
Wrote and verified address 0x0800f178 (100.00%) Done.

To program custom fw:
~/stm32flash$ sudo ./stm32flash -w fs-t6.bin -v /dev/ttyUSB0

In Original FW you go to Menu, System, scrol down to "Firmware Upgrade".
In AR-T6 go to Menu, System, Version page, Menu (pres&hold SELect roller).

Thanks go to Martin, here is his writeup.

Sunday, November 23, 2014

FS-T6 student cable

FS-T6 has a build in connector for another radio to be used as a trainer. However, the connector is rather unusual S-VIDEO one.  There is a discussion about making a cable in the rcgroups:

The connector is on the back of the radio. It has 4 active pins and it uses connector shield for ground.  Using standard s-video (see above wikipedia link) pins the signals on the radio are:
1 - PPM TX
2 - PPM RX
connector ring - GND

The signals that needed to be connected between the two T6s are #1 and #2 crossed (ie TX of one radio goes to RX of another and vice-versa). I have decided to cross both PPM TX/RX and Serial TX/RX to avoid output shorts...(ie output driver another output).  Maybe one day we find a use for two radios communicating through a serial link? This essentially creates a "null modem" cable.

To make a cable you have 2 choices: 1) buy 2 plain connectors and solder the wires 2) rewire a standard s-video cable. Being a frugal guy I have opted for #2 (s-video cables are available for <$4 while single s-video connectors are more). However, standard S-VIDEO cables do not connect the grounds and connections are straight. Here, to connect two T6s you need to "cross the streams" and add the ground wire.

Start with taking out the outside rubber. I cut the connectors first, Start cutting from the cable side to the connector to avoid cable damage (if you slip the knife). Then pull the rubber off.

Next. Cut the cable in half In order to cross the streams. You may decide to do it in the middle (like I did). Or close to one of the connectors (if you want to wrap it with connector later).
After cutting, unwrapping the shields, stripping the middle wire and re-soldering crossed over, I have wrapped them in electrical insulating tape. Note, the cross over is 1<-->2 and 3<-->4 which are on different cables (connect shield of one cable to center lead of another for each cable.).

Than next I have added the ground wire. I have soldered it directly to the outside metal ring on both ends, then slipped the wire into a groove cut out in the connector plastic.

The finished cable looks rahter nagly (nasty&ugly) but it works. However, the s-video connectors do not make solid mechanical plug. So if your plugs fall out as much as mine you'd want to lead the cable through the radio handles first and then plug it in. 

My son and I flew together last week! It works!

Tuesday, October 28, 2014

FS-T6 and SWD hack

Preparing the FlySky-T6 RC TX for development with SWD. 

SWD = Single Wire Debug

  Well, the SWD at a minimum requires 3 wires: clock, data and ground (great marketing though).  In addition, it is very handy to add a reset line (nSRST_.  This line would reset all the devices around the core CPU in the SoC chip in addition to restarting the CPU core.  Otherwise, starting conditions would differ form run to run and I often see hangs.  I have tried to use the 3 wires (aka ST-LINK V1, as featured on STM32FVLDISCOVERY with CPU similar to the T6's stm32f1xx chip). I did not like it.  Hence later, I have hacked in the 6 pin connector.



Discovery stm32f1discovery is equipped with 4 pin SWD.  All other discoveries AFAIK are ST-LINK V2 and come with 6 pin SWD.  Remove the jumpers as shown on left to disconnect the on-board SWD control from the CPU (the one that also plugs into your PC's USB; discovery docs) then you can use the SWD connector to pulg it into T6.

Notably, the V1 and V2 also differ in software. and in general the V2 is much more reliable according to openocd references.

4-pin SWD


Here are the schematics for 4,6 pin and full 20 pin SWD connector as seen on T6.

Note that SWD lines are also used by JTAG. Through some signaling magic CPUs would cpu obey (switch into) SWD instead of JTAG.

The 4 pin is identical to the first 4 pins on 6-pin connector - handy!.

6-pin SWD
The VDO pin (pin 1 of the connectors) is not used - it is disconnected on discovery boards. I tied it to +3V3 on T6's side.

Connections to T6

T6 20-pin "full" debug connector

I have connected the following:
 U2(T6)    CN3 (DISCO)
+3.3V P1---P1 VDD 
TCK   P9---P2 TCK
GND   P20--P3 GND
TMS   P7---P4 TMS
GND   P18--P6 SWO

Also the SWO is not available on F1xx CPU (this is used normally for trace output). This schematics is from ar-t6 .

Here is the final result. Pin #1 is marked with a sqare, left lower row.
I have also cut out small opening for a standard 6-ping header (female) that I have crimped and than hot-glued to the case. So now I can close the T6 and have it ready for flying in no time. Additionally, I found a 12V PS with correct plug and can now power T6 on my desk w/o batteries - this is a bonus and not required.

Let me know.
...sorry for formatting - blogger is a pile of streaming google...and google really stinks recently...

Monday, October 27, 2014

Embedded software with Eclipse, Arm, Stm32fxxx, OpenOCD to develop FlySky FS-T6 trasmitter firmware

This is a very terse dump of my experience of setting up a development environment for developing software for STM32Fxxx series of ARM processors. These CPUs come in a VERY inexpensive "discovery" boards (e.g. STM32F0DISCOVERY,  STM32F3DISCOVERY, STM32F4DISCOVERY) - very fun to toy with (usually $10-20 and no need for any "emulators", "jtags" programmers etc). So this is cheaper then the famous "arduino" and you get a 32bit processor with tons of peripherals. I actually used this to start developing firmware for FlySky-T6 RC transmetter following the fantastic work here.

In order to develop embedded software one usually needs: text editor, build tools, programmer/debugger tools. Here there are in order:
- Eclipse
- gnu arb toolchain
- openocd

The Eclipse is an IDE (Integrated Development Environment) that integrates editor, project management, build, debug documentation in one common, portable, extendable GUI.

The gnu arb tool chain provides compiler/linker/stdlibraries/debugger to produce executable code.

The openocd provides access to hardware. It can communicate with hardware debugger agent and provide flash memory access and debugger server that then can interact with gdb (the gnu tools debugger). An ST-LINK/ST-UTIL (texane or STM versions) can be used instead as well.

Eclipse/GNU/OpenOCD setup


this usually ends up a "java" development without CDT ("C/C++"). I have downloaded Eclipse "Luna" .
Install CDT Plugin (skip this if you've donwloaded a CDT-Eclipse):
in the above find correct "p2 repository" link --> Copy to clipboard
in eclipse: Windows->Install New Software->Paste Link
install main CDT + GCC and HW debug
Install GNU ARM Plugin
install "p2 repository":
Install GCC ARM toolchain (from launchpad):
setup for win32 or in debian/ubuntu apt-get install
Creating first project
select "C/C++" perspective - on the right upper, if not there "+" (add) it
file->new C/C++ project select one for your CPU; see below

WARNING - after days of somewhat working debugger I faced gradual dysfunction: 1) eclipse stopbbed being able to interract with openocd in "pipe" mode (ie when it launches oocd itself) - I have switched to running oocd manually. 2) later it decided to gray out (disable) all debug buttons even after successful start and hitting a breakpoint. This was described in this thread: Solution was to uninstall "GDB Hardware Debug support" (the openocd pluging started to work!).

OpenOCD - Windows

Specific to the ar-t6 firmware:
On windows you'd get 2 build errors - can't find "echo" and "make" - solution is to steal them from codesourcery as per
but an alternative would be to install gnuwin32 and add them to the path.

Based on similar w/ CodeSourcery:,with,opensource,toolchain,codesourcery,eclipse.html
usb drivers for ST-LINK:
alternatively (not adviced) Options->show all->ST-LINK UpdateDriver

There may be a need to install libusb0 (can't tell if it got installed with zadig or came with ST-LINK installation). Just in case you may want to install it from here:

Then in eclipse: but it does not run openocd so had to manually run
"openocd -f stm32f0discovery.cfg -s c:\home\openocd-0.8.0\scripts"

The solution is to change to windows backslashes. Make sure the cmd params are correct as eclipse would not give you any hints as to why it failed to start it.

Other/T6 related

STM32F1xx standard peripheral library
but no need for it as it comes with ARM plugin...

I see occasional communication problems between eclipse (gdb?) and openocd debug server. Killing the openocd process from Task Man restarts system to working condition.
git clone the ar-t6 into your "workspace" directory. the proceed to open project. If you do not know eclipse you will go through world of pain as it is not intuitive. That's okey, it will pass...

The original project builds fine with gnu tools (with some warnings about code sourcery paths) . It contains CMSIS library (arm and stm parts).

One needs to setup openocd "Debug Configuration" as per

Also in addition I have setup a special stm32f1-fst6,cfg (saved into openocd/scripts/board)  :

# This is an FlySky T6 base on STM32F100R8
source [find interface/stlink-v2.cfg]
source [find target/stm32f1x_stlink.cfg]
# use hardware reset, connect under reset
reset_config srst_only srst_nogate

That's what goes into "config options" in the "debug" tab of debug configuration :
-f stm32f1-fst6.cfg
Try this from CLI
openocd -f stm32f1-fst6.cfg

It should report the chip id and number of hw breakpoins etc. and then wait for GDB to connect.

Also in the debug configuration that you've set up per "openocd eclipse setup" I had to change the "debug/gdb client setup/executable" to explicitly say "arm-none-eabi-gdb" as the at-t6 project does not seem to define standard "cross-" macros. The debug configuration got committed to github as "ar-t6 Debug.launch" but it's a "Windows" one.

Wednesday, April 20, 2011

Kitesurfing: Leading Edge Blowup Kite Repair

(experimental, ie do not follow)

My Flexifoil Ion3 9m blew up. To add insult to the injury it blew up on the beach, in my hands when I was inverting it to pack and go home. Darn! Looks terrible. I simply think it just got old and tried to quit on me. No such luck, buddy! The quitting I mean, not getting old.

So here is my attempted, DIYig (DIY in garage) revival report. Some things worked, some were messed up. I am yet to try to fly it...

The repair was a two step process: the bladder and the canopy. Since I am lazy by nature I decide not to pull out the bladder completely but just slide it out of the tip. This was possible since the damage was close to the tip.
So here it is, the bladder with a fist-size hole. They say, cut it open and glue a patch from the inside. I say no need to fix a hole by creating another hole.

I removed the air connection from only one strut and rolled the bladder so it does not get in the way.Then I used some sticks to stretch damage area.

I used a bigger-then-palm patch out of an old bladder and put it into the bladder through existing opening (technical term to describe a hole). Just made the patch way oversize so when glued with AquaSeal, the glue would not have a chance to glue the bladder's walls together. Here the black marks the edges of the patch (it's inside the balder). The glue already applied through the hole (I have cut out the original damaged area from the blown-out material).

I have also applied another patch from the outside. I have spread the glue to keep the edges of the outside patch glued to the bladder.

After 12 hours under load, the glue turned yellow. I have not used AquaSeal before so I have not idea if this is OK....It feels flexible and strong.

This is how it looks like cured.

Anyway, the only other problem was that there were small pockets of air left between the patches. But is this a problem really?

This part was relatively easy. The stitching required patience and a lot of ...
Here it is, the top seam opened to make more space for sewing. I had only a fairly thick dacron from my boating days. I have also used the double sided sewing tape 3/4" (the white strips already attached to the edges of the damage. I have decided to put a single band of dacron and sew it in.

In order to help with alignment I first applied a insignia cloth to the outside. This helps keeping the edges together and in good place.

Then I placed the dacron into the double sticky tape. The insignia cloth was a second take idea. I found that the sewing tape is not sticky enough to hold the edges together.

Sewing the seeds of love..ahem...adjusting my flaky walking foot machine is always a challenge, esp when I have not used it for a few years. She's got rusty, so did I.

Four rows of zig-zag from the edge to the edge. I had to rip it out only once when the sail cloth got sewn in. Only once I swear!
Then I got a brilliant idea to strengthen the cloth and put a spinnaker repair tape around the edges. Esthetic's got lost in the process (the tape is white).
But where did the bladder go? I dropped it rolled into the LE shoulder. Kept it nicely out of the way.

Sew him up, doc! I had to get the bladder out. Stretch it and somehow pray I will not sew it in while closing the leading edge.

Here, under (minor) pressure test....It worked!. Just royally miscalculated (read "screw up") one small detail. The edges got quite strong with extra spinnaker tape and with the dacron (see: it is nicely going all the way from edge to edge). But...unfortunately, the dacron I used way thicker then the original cloth and hence I could not fold it. Darn!  This made the repair downright ugly...

the good

This is plausible result. Kite survived nightly pressure test. and looks fine on the outside.

the bad and the ugly

Note the LE deformation. I suspect it could be a result of original damage and/or my sewing. It looks like the circumference is smaller in this area. Perhaps, I should redo the top seam. One day. Perhaps.

Oh, well. I only meant the repair as an experiment....I do not think I'd take it into waves anymore. But on flats or as a learning kite it is still OK.

Monday, December 20, 2010

YAPF - Yet Another Pricture Frame

with "viewer presents awareness" and geeky frame. 

Yup, yet another digital picture frame made from an old laptop. Added value: "viewer awareness intelligence". Say what? Ohh, nothing big. Simply a PIR (passive infrared sensor) to detect motion and turn on/off the back-light lamp. This prevents the lamp from burning out too quickly. To make things more interesting, a frame made out from discarded industrial printed circuit board. Perfect for the geek's house, ain't it?

Why ?

I have few of these long-obsolete, unwanted laptops in my garage and a desire to do something with them. They work...sort of. You can run Win95 on one, a Win3.1 on another and DOS on the oldest one. OK, some of them are too old. I have picked a ca.1997 Omnibook 800CT (Pentium MMX 166MHz/80MB RAM 800x600 10" TFT LCD). 

Now what?

Obviously this has been done for years. Short recipe here: 
  1. Get a CF card (>=128MB) and a laptop IDE-to-CF adapter (eBay)
  2. Using your USB card reader and your Linux Desktop (you have one, right?) install GRUB into it and a (preferably small) Linux distro.
  3. Install a picture viewer of choice and make it run at start.
  4. Copy pictures to a subdirectory.
  5. Remove the screen hinges and the skirts (front plates) from the laptop, then build a frame around it.
  6. Plug the CF & adapter in your laptop, reboot.
  7. Enjoy.

Add salt to taste.
Here are hints
CF card & adapter in IDE connector
  • Use GRUB  pre-2 version (I used 1.98). Newer may not work with old machines. There is plenty of help on-line.
  • I used TinyCore, a 10MB distro. On Omnibook 8xx series the Xvesa does not work so I had to install Xfbdev.
  • For picture viewer I used FEH, avaliable for TinyCore as add on package. The only downside of FEH is lack of transitions, but with weak CPU this may be actually be a benefit.
  • Add a script to start FEH after X started. The script that starts FEH goes into /home/tc/X.d/ It contains:
    • feh -rzFD60 --hide-pointer /mnt/hda1/Pictures &
    • as you see the pictures are in /mnt/hda1/Pictures (ie in the directory /Pictures in the top of the drive
    • the rest of options tell feh to do randomized slide show changing picture every 60s

Frame w/o laptop
Mechanical stuff

The frame is make of two identical PCBs one with elements the other blank. I have taken them from a pile of garbage. By size they are big. Old PC motherboards may be of use here. A dremel and angle grinder with cutting blade are your friends. All is held together by 6 stand-offs. The laptop slides in and is screwed into the front PCB.

PIR sensor aka "viewer presents awareness"

This was the most fun. It really had few parts: reading the PIR sensor, controlling the backlight, implementing the script to bind them all. 

To Port or not to Port

Laptop with PIR and PP connected
The CPU part is tackled under.
When this laptop was designed (ca.'95) there were no USB ports. But Parallel and Serial were in full swing. Both ports are easy to interface with and both have some lines that can be directly controlled (Serial has modem control likes, while Parallel is pretty much fully controllable). However, for the ease of software implementation I have chosen Parallel as it can be accessed from shell scripts through /dev/port. The down side of Serial is a harder control from scripts and its +/- 12V levels. So parallel it is.

However, my laptop (like many other) has and open-collector outputs that are internally pulled-up by 1kOhm resistors. Way too much for the Parallax PIR sensor I was planning to use (it ends up about 4mA drain). so I had to add a transistor "amplifier". Here is a good spill about the sensor and how to connect some load to its "Out" pin. The transistor output (collector) got connected to pint #15 of the port (which leads to bit #4 in STAT register).

Let there be...darkness

Modified inverter and PIR output amplifier.
All powered from +5V available on the inverter.
How to control backlight? There are more then a few ways. Normally, newer hardware would have ACPI which has backlight control. But my laptop has older APM which does not. So much for direct control. Another idea would be to decipher the keyboard and pretend a  "PWR" button press, which turns the display off (but let the CPU to continue). This proved hard to interface as the keyboard is connected through the thin "foil" connectors. So, in desperation I looked at the CCFL inverter and, the proverbial "bulb" went on in my brain. The inverter is build around LT1184CS chip, which has a "shutdown" pin. Bingo! Well, not quite. A little probing showed that the pin is shorted to +5V by some buried trace. So I got out my 6-pack of whoop-ass and lifted the pin. Added pull up 6kOhm resistor (probably not necessary as PP has pull-ups but I did not want the darkness when not in control). Then connected it to pin #14 (bit #1 in CONTROL register). 

Scribbling the scripts

I choose to implement the monitoring of the PIR in shell scrpt. There are 3 scripts: rdport, wrport and monitor. All placed in ~/.local/bin and invoked from .profile. Granted, I could simply hooked up the PIR to a timer such as NE555 and control the backlight directly. But writing script was more fun. As benefit, the scripts can log activity in my house (do not know why I'd need it though).

Again, few obstacles to be solved:
  1. how to read/write a port
    • access through '/dev/port'
    • must be root hence 'sudo'
    • use dd with seek/skip sudo dd bs=1 count=1 of=/dev/port seek=$1
    • convert a string '123' to actual byte :  echo -n $2 | awk '{printf("%c",$0)}'
    • convert byte to a sting: hexdump -e '/1 "%u"'
  2. how to interpret and generate binary values
    • motion=`dc $pir 8 xor 8 and p`

The script to read any ISA port 'rdport [addr]':
sudo dd bs=1 count=1 if=/dev/port skip=889 2>/dev/null | hexdump -e '/1 "%u"' 

The script to write any ISA port 'wrport [addr] [val]':

echo -n $2 | awk '{printf("%c",$0)}' | sudo dd bs=1 count=1 of=/dev/port seek=$1 2>/dev/null 
There is a small problem with this script as I cannot write 0. I think the busybox implementatino of awk's prints has problems printing 0 as this is a string terminator in C.

A script to monitor the PIR state and control the CCFL inverter "shutdown". This is the "brain". The addresses of PP CONTROL and STATUS registers are 889 and 890. The script only updates the 'shutdown' signal when its state actually changes.

The jest:
  • loop forever
    • check the sensor state
    • if motion detected update "last motion" time stamp
    • if "last motion" time stamp tool old (here 300 seconds) then turn off the backlight
    • otherwise turn on the backlight
# monitor PIR sensor and control backlight

# handy function for time-stamping
now() { 
  echo -n `date +%s` 

# initialize start conditions
maxElapsed=300 # 300 SECONDS = 5 MIN

# loop forever
while true; do

  # read and check PIR (bit #3 of ParPort hence mask is 2^3=8)
  pir=`rdport 889`
  motion=`dc $pir 8 xor 8 and p`
  if [ $motion -ne 0 ]; then
  # see if enough time elapsed since last registered motion
  elapsed=$(expr $(now) - $lastMotion)
  if [ $elapsed -gt $maxElapsed ]; then

  #echo $pir $motion $lastMotion $elapsed $expired $off

  # if changes the state of backlight then apply it
  if [ $requestOff -ne $off ]; then
    if [ $off == 1 ]; then
      echo -n 'OFF: ';date;
      wrport 890 2
      echo -n 'ON : ';date;
      wrport 890 1



I'd like to have Forward/Backward buttons.
Have it WiFied to my picture archive (get a better laptop for this).

Make it serve beer.
Go on line and download some ...wait!


Monday, October 11, 2010

Kitesurfing: Replacing a strut bladder with U-Stick orange bladders

Here is a story of a bladder (replacement) on an inflatable kite.

Twice-Broken valve
Recently, I had a failure in my Flexifoil 9m Atom3 after I left it simmering in the sun for several hours (at Rio Vista, CA.) After having an "interesting" session with half-deflated kite I was faced with a repair. The heat caused delamination of the strut valve from the bladder. I have had local repair shop repair it. They glued the valve back but the repair looked terribly (with some part of bladder glued together, ripped apart and left hangin and bladder folds). I have reinstalled it anyway and tested it overnight. It held the air. I did not go out for several days (no, the kite was no longer on the sun).
Next time I have inflated it on the beach the kite quickly lost lots of air. I discovered that although the glue held, the valve become cracked and it had a serious leak. Apparently the repair damaged the valve base. The damage looked like it was heat induced. I bet it was overheated during the repair (the valve is usually completely unglued by "coocking" it). So much for "professional" repair.

Orange and original bladders.
So, a full bladder replacement was in order: U-Stick orange bladder and valve. The Airtime Kite people were awesome. They quickly advice me what I should use. The strut valves, both on main and strut bladder are called "option" as you can choose different stems. Flexifoil has a 11mm valves with straight stems. There is also a "replacement" option valve which does not have "options" as it comes only with straight stem. Also, Airtime has nice on-line bladder selection tools. My kite needed 50cm bladder. The valves fit the opening in the kite and did not need rings. Ordering and shipment was a snap, thanks Airtime!

I followed instructions attached to the bladder and valve. However, there were few small surprises.

The 50cm bladder is visibly much bigger then the original Flexifoil one. Too big is OK as the kite will restrict the expansion, too small would be bad (too much stretch). The original bladder was also 50cm (just much smaller). 

The material is more brittle sounding (it sounds more like a "shopping bag" while Flexifoil's is more like "sex-rubber", if you know what I mean.) Just observing the visual difference which has nothing to do with other physical properties like strength. I just said "oh well it must work fine."

REALLY be careful when cutting the hole in the bladder for the valve. The bladder is completely air tight when shipped so pulling it apart is hard. Never thought that vacuum can be so hard :-)
Bladder prepared for surgery

When sticking the valve there were more surprises.

The bottom of the valve protrudes from the base so it is perhaps better to use soft surface to glue on, like a towel.
Bottom of stem protrudes beyond the base
It is hard to align it with the hole before the valve sides will start catching the bladder and when they do, it is over; perhaps a helper could stretch the bladder flat when you align the valve and stick it, mine cough bit early and got slightly misaligned with the cutout.

The valve glued to the bladder.
The diameter of the opening in the end of strut is so small that I had to bend the base of the valve to fit it in. Then I had to push it in through with some force. Needed to get a bit medieval with it, but it worked. The rest of the way was traveled with a "string attached."

Size matters?

The bladder is so much longer than the original even though I followed the instructions and folded top and bottom inside to match original length. I have folded it more so it flashed with the pocket.

Too long?

The valve is a bit shallower then the original so the pipe between main the strut seems too short and bends the new valve. I wonder how it's going to work long term?.

Too short stem?

So far so good, the kite flies and makes his owner smile. The replacement was $35, a mare $15 more then the "professional" repair that failed.