Bootloader over UART with Nucleo-64 Board(MB1136) - No response?

[gflyer]

Hi all,

I recently purchased a Nucleo-64 board with a STM32F401 and started programming it, while doing so, I accidentally re-configured PA14 & PA13 used for SWD and used by the ST-Link to program the MCU to be GPIO pins. To fix this, I thought of re-flashing the MCU with updated firmware where SWD is enabled again over UART. I tried this by pulling BOOT0 high, a USB-Serial adapter on PA10 & PA9, and doing a power cycle on the board. The USB connection is exposed as COM11 on Windows, so I tried to connect to it using CubeProgrammer but got the following error:
"Error: Activating device: KO".

I have set the baud rate to 115200, parity to even and the stop bit to 1 - But no dice. I then tried to use Realterm to send raw HEX (0x7F) to the MCU but got no response. I figured the issue might be my USB-Serial adapter, but a simple loopback test proved the adapter to be working. Worth pointing out, maybe, is that my adapter is 5V - But my MCU's datasheet states that PA10 & PA9 are FT so 5V tolerant, so that shouldn't be an issue if I'm not mistaken.

Am I missing something?

Thanks!

[Tesla DeLorean]

Pulling BOOT0 HIGH should be sufficient to stop your code running, to the point where the ST-LINK connection should be able to erase the part, unless there's an electrical issue. So via the SWD connection, or drag-n-drop of a binary to the USB MSC

[gflyer]

I have pulled BOOT0 high and connected the board to my PC through the micro USB connector on the ST-Link part of the board as you said, but it still fails to connect:

19:38:08 : UR connection mode is defined with the HWrst reset mode
19:38:09 : ST-LINK SN : 0672FF333041383043202759
19:38:09 : ST-LINK FW : V2J46M31
19:38:09 : Board : NUCLEO-F401RE
19:38:09 : Voltage : 3.26V
19:38:09 : Error: Unable to get core ID
19:38:09 : Error: No STM32 target found! If your product embeds Debug Authentication, please perform a discovery using Debug Authentication

I believe this approach wouldn't work if I disabled SWD on my firmware - Or is it that SWD gets re-enabled when using the built-in bootloader? If it is the latter, I think my board has some electrical problems I have to look into, but I hope not :).

[Tesla DeLorean]

Check the jumper pair (CN2) on the NUCLEO, that connect the SWDIO/SWCLK pins to the local target (F401)

Make sure the board is not on a conductive surface (foam or mat)

[gflyer]

I have removed the jumper pair CN2 and LD1 on the ST-Link part of the board is green. The user manual states the following:

• Green LED On: after a successful target communication initialization

But I still get this error in CubeProgrammer:
Error: No STM32 target found! If your product embeds Debug Authentication, please perform a discovery using Debug Authentication

Whether the jumper pair on CN2 is removed or not doesn't seem to have any effect for me.