I was using openTX 2.2.0 (BUILD 85863358, 2017-05-13) and followed the instructions given in Frsky's latest YouTube tutorial.
The upgrade seemed to work on first glance („WRITING EEPROM….“) but failed in the process. Now the X8R’s leds don’t light up anymore and it is not recognized when I try to flash it again. I've made a short video.
I am certain that I've made all the connections right, and although I am not using the standard NIMH battery but a 3S LiFe i am also certain that this is not the problem. The Taranis is supplying 9.8V to the receiver, this beeing barely inside its voltage range of 4-10V. The builtin regulator is working fine, providing the STM32 with 3.3V.
Both X8Rs are well out of warranty (built 20/12/2013), but nevertheless I’d like to make them work again.
I'm aware that there is a similar topic on these forums, but this is a bit different, since I’ve most likely managed to corrupt the Frsky bootloader on the STM chip of the X8R.
I know that the STM chip has an internal bootloader and that i should be able to flash it via an USB-serial-cable (e.g. FTDI) and an STM Tool (this or this). I've already traced out the necessary connections:
As Kilrah stated in the other topic, Frsky most likely won't provide a full unencrypted firmware image. What I'd like to see them do is provide their bootloader in unencrypted form, so that one can flash it via the builtin, "unbrickable" STM bootloader. Then one can use the established methods ("Flash external device" in the SD-Card menu on OpenTX, FUC-3 and smartPort update tool, etc.) to flash the encrypted firmware.Kilrah wrote: ↑Fri Apr 04, 2014 7:01 amThe problem is less the programmer than the fact that you would need the unencrypted firmware image that is installed at the factory, which FrSky will obviously not release to the public.
At this point nobody has access to them, but we are working with FrSky to establish trusted "service centers" who have the knowledge and equipment to handle that kind of issues
I should know in a few days if I can take care of yours.
I've already contacted Ray from FrSKY about this.
EDIT: I've just realized that this makes no sense, assuming that the bootloader has the key to decrypt the .frk firmware images.
If FrSky does not provide unencrypted firmware, they can't / won't hand me the key to decrypt their firmware. Thoughts on this?
Are there other options to get my two dead X8Rs back to working condition?
Do you have an idea how and why this happened?
I know that I’m not the only one encountering this problem:
https://fpv-community.de/archive/index.php/t-61170.html and https://www.rcgroups.com/forums/showthr ... ked-X4R-SB .