STM32F405 wont flash

[EOpitz]

Hello everyone, I have had problems flashing a STM32F405 from a 3D printer board, I have not managed to flash via DFU and with a STLink-V2. Here is what I have done.

- First, the board has a HID bootloader, which by connecting jumpers between BOOT0-3.3V and BOOT1-GND allows the board to enter DFU mode. With this, I managed to flash a bootloader for the connection of CAN accessories (Katapult - Canboot). After two unsuccessful attempts the bootloader was not operational.
- Second, I again connected BOOT0-3.3V and BOOT1-GND, entered DFU and with STM32Cube I erased the whole chip to reprogram bootloader and firmware.
- After the above, when reconnecting the board to the stm32cube with and without BOOT0-3.3V and BOOT1-GND connected the board fails to enter DFU.
- Finally, I tried connecting a STLink - V2 clone, updated the firmware on it and tried to connect to the board, however I get the image error (DEV_TARGET_HELD_UNDER_RESET). The connection through STLink was tried with and without RST cable from STLink to the board, and through the options Software Reset, Hardware Reset.

Attached is the schematic of the board in question.

Github Schematic - Gemini V3 Board 

Any suggestions on how to proceed?, I would appreciate it.

[AScha.3]

Hi,

try in Programmer settings : software reset , mode normal.

(V2 clones have no working hard reset ! )

+ enable :debug in low power mode

-------

And if after reset, with BOOT0-3.3V and BOOT1-GND (check: reset hi again...)

CubeProgrammer in DFU mode -> no response from chip --- maybe you killed the chip. :(

[EOpitz]

Edit:
Thanks!