Speedybee F405V4 freeze on Boot

[Morpheus235]

Hi everyone,

I bought a brand new Stack (F405v4 & 55A Bls ESC) from Aliexpress (Maybe a Clone?) a while ago and never really got around to putting it into a Build. I flashed this FC with INAV and seem to have some Issue with First Boot Setup as the FC LED flashes a few Times (3 Times, Pauses, then 6 more Times and staying lit on the 6th Time) and seems to freeze. After flashing connecting to the FC via Bluetooth or USB Serial never worked and only timed out. Meanwhile flashing Betaflight or Ardupilot worked flawlessly weirdly enough. Could somebody maybe point me in the right direction for debugging this? I do have an STLink V2 available but was not sure if the Pins are broken out on this FC. I tried different Versions of INAV (6, 7 & 8) and also used different USB Cables and Versions of the Configurator (Linux/Windows) on different PCs. Also I have tried running the ImpulseRC Utitlity but I never had any Issues accessing DFU or Flashing. I also compared the Target to Betaflights but could not spot any real Difference but nevertheless tested running Custom Builds with Various Sensors removed.
Photos of the FC:


Screenshot from Betaflight:

I would be happy for some suggestions on how to debug this

Thanks
Daniel

[sensei-hacker]

I see you have a clean board with nothing connected, so that helps eliminate a lot of possibilities.

You've probably done this already, but:

After flashing with full erase left on, close Configurator, disconnect the flight controller so it powers off.
Then reconnect the flight controller and re-open Configurator.

One thing that can cause a problem is if you turn off full erase (erase the settings) for the first flash, it ends up reading whatever junk bits happen to be laying around in the flash as INAV settings. If what happens to be there is Betaflight settings, that work about as well as trying to read this as English:

यह अंग्रेजी नहीं है
yah angrejee nahin hai

Also, the serial connection used for flashing can leave a bit or two hanging around in buffers that messes with connecting again, so that's why we might power down the board, close and re-open Configurator to be sure.

The other thing, which you've probably already done, is triple-checking to be sure you're flashing the SpeedyBee V4 firmware.

[Morpheus235]

Yes I did, restarting the FC only ends up in the Same FC LED freeze. I am always using the SpeedybeeF405V4 Target and flashing my other FCs work without Issue. Also the Sensors seem to Match the Target (AT7456E, DSP310 and ICM42688P). Maybe a Issue with the SD Card? In Betaflight it is detected without Issue. Also booting with or without an SD Card does not matter.