AIDeck GAP8 Chip not starting or connectable through JTAG.

[cookacola]

Hi! I am having an issue with the AI Deck 1.1 where after flashing some new firmware to the GAP8 using a DORY compiled neural net and image streaming through the JTAG (and specifically using the NanoCockpit implementation), the GAP8 seems no longer functional, but the ESP/NINA side still seems fully functional. When attempting a recovery by flashing the JTAG bootloader, the JTAG does not seem to be able to connect to the GAP8 at all and returns the following:

Warn : Interface already configured, ignoring
TARGET create
Info : core 0 selected
Info : gap8_adv_debug_itf tap selected
Info : adv_dbg_unit debug unit selected
Info : Option 7 is passed to adv_dbg_unit debug unit
GAP8 INIT TARGET
Info : clock speed 1500 kHz
Error: JTAG scan chain interrogation failed: all ones
Error: Check JTAG interface, timings, target power, etc.
Error: Trying to use configured scan chain anyway...
Error: gap8.cpu: IR capture error; saw 0x0f not 0x01
Warn : Bypassing JTAG setup events due to errors
GAP8 examine target
Init jtag
Initialising GAP8 JTAG TAP
Info : adv debug unit is configured with option BOOT MODE JTAG
Info : adv debug unit is configured with option ADBG_USE_HISPEED
Warn : CRC ERROR! Computed 0x00000000, read CRC 0xffffffff
Warn : CRC ERROR! Computed 0x00000000, read CRC 0xffffffff
Warn : CRC ERROR! Computed 0x00000000, read CRC 0xffffffff
Warn : CRC ERROR! Computed 0x00000000, read CRC 0xffffffff
Warn : CRC ERROR! Computed 0x00000000, read CRC 0xffffffff

Additionally, before this issue occurred, during previous neural net deployments (lighter and without attempting image streaming), the GAP8 was already finnicky and would only turn on after we put it onto the pins lightly.

[gemenerik]

Hi, flashing anything with JTAG (which does not support the bootloader offset out of the box) will wipe the OTA bootloader. This may be what you are experiencing?

If you want to restore the OTA bootloader (to clarify, you don't need it if you are OK with just flashing your nets using JTAG):
It may be elementary but can you run verify you attached the JTAG cable correctly, attach the deck correctly, the battery is fully charged and the Crazyflie is turned on, and then retry flashing the bootloader?

Can you explain "the GAP8 was already finnicky and would only turn on after we put it onto the pins lightly" a bit more? Do you mean the AI-deck instead of the GAP8? What does it mean to "put it onto the pins lightly"?

What firmware release are you running / did you branch off from?

[cookacola]

Hi, yes I have verified that I have attached the JTAG cable correctly, and the deck is in the correct orientation, the battery is fully charged, and the Crazyflie is turned on. Additional context I can provide here is that we have previously attached the deck in the incorrect orientation a couple of times in the past, but corrected the mistake after discovering it. The JTAG connector pin was bent a little bit but we also bent it back into being straight.

Here is the output when trying to reflash the bootloader under these conditions:

Open On-Chip Debugger 0.10.0+dev-gb84d97ec4 (2022-04-20-14:26)
Licensed under GNU GPL v2
For bug reports, read
http://openocd.org/doc/doxygen/bugs.html
debug_level: 0

DEPRECATED! use 'adapter speed' not 'adapter_khz'
DEPRECATED! use 'adapter driver' not 'interface'
TARGET create
GAP8 INIT TARGET
Error: JTAG scan chain interrogation failed: all ones
Error: Check JTAG interface, timings, target power, etc.
Error: Trying to use configured scan chain anyway...
Error: gap8.cpu: IR capture error; saw 0x0f not 0x01
GAP8 examine target
Init jtag
Initialising GAP8 JTAG TAP

And it hangs here^

By "finnicky" I mean that in the past, when mounted tightly (pushed down onto the pins), the deck's GAP8 chip did not seem to boot up properly (while the ESP did). However, when we removed it and put it on the pins lightly, as in we did not make the pins connect tightly, the GAP8 seemed to boot fine and ran, albeit briefly sometimes. We suspected that it may have been a power or connection issue? But now it just does not turn on completely. ESP is fine though, and powers on reliably. This is confirmed via a blinking LED and working JTAG flash for the NINA side.

We are running the latest release of the Crazyflie firmware: 2026.04.

Additionally, with our remaining, different, working deck, to make the power connection more reliable, I have mounted it below the battery but on top of the STM32. That seemed to have solved the issue of the GAP8 reliability issue. Let me know if this is a safe configuration for the deck and if it will cause it to be damaged.

[ataffanel]

I do not have much experience with the AI deck but until Rik is back next week, I can try to help a bit when it comes to the deck system.

As long as you are inserting the deck the right way around, you can safely insert it anywhere in the stack.

As for the connections issue, you may try to look at the deck connector: there should be 2 metal part that squeeze the pins inside, if they are deformed they will make bad contact. You may try to pry them carefully with a sawing needle to make them make better contact.