(pixracer clone) STM32F427VIT6 Dies after power cycle after SWD flash

[SkyArise]

Hey, I made a pixracer clone using STM32F427VIT6, it works after i flash it with SWD using CUBE prog. 

but it wont turn on after a power cycle. 

the system works fine after flash as long as I don't disconnect power. 

I have added the schematics. 

BOOT0 is pulled down with 10k 
BOOT1 is pulled down with 10k and connected to 3v3 though boot switch
nRST is pulled up with 10k to 3v3 

I thought its nRST 3v3 stability issue, I manually tied nRST to gnd to keep it In restart mode till 3v3 stabilise , still same behaviour. 

I also disabled the 24mhz HSE, still the same behaviour, works after fresh flash, dies after power cycle. 

The schematic is a clone of MRO pixracer flight controller, only difference is I didn't use a power supervisor , instead i pulled nRST to 3v3 with 10k.

any inputs are appreciated 

thanks!

[TDK]

With the debugger connected, does it work if you hold NRST low briefly to reset the chip? If not, connect with the debugger without resetting the chip to see where it's at and why it isn't running.

Consider adding debug statements to UART7 so you can get information about it booting up.

I don't see any problems with the schematic that would explain the issue.

[SkyArise]

hey, I did try pulling nRST low, didn't work. 

according to stm cube, its stuck somewhere in bootloader.

also I found BKP0R = 0x00000000

I am newbie with stm32 , I was just trying to clone ardupilot FMUv4 (pixracer) the schematic is also referenced from pixracer with only difference being I used 10k pull up on nRST while pixracer uses a voltage supervisor (mcp131). 

I haven't modified the firmware, I am using ardupilot pixracer firmware on it (it works on off the shelf Flight controller) so I guess the firmware and boot loader is fine. 

 

 

[TDK]

If it's in the bootloader, then BOOT0 probably isn't low on startup.

Introduction to system memory boot mode on STM32 MCUs - Application note