Using st-link of another nucleo board gives core is held in reset error

[abcdef]

Hi,

I have a nucleo L053r8 and a nucleo f401re boards. I want to use the st-link of the L053 board to load code and debug the f401 board. I removed jumpers from CN2 and connected the pins of CN4 connector of l053 board to the correct pins of the f401re board.

I'm using keil and it gives me @Core is held in reset error when I try to flash the microcontroller.

I tried to do this: on the f401 board, I removed jumpers of CN2 and connected the pins of CN4 of f401re board to the correct pins on the f401re board. Long story short, I tried to use the embedded st link on f401 board as an external st link. It works without errors. So I dont understand why using the stlink of the l053 board doesn't work.

Any idea or suggestions to solve or to understand the problem?

Thank you

[Tesla DeLorean]

Seems an oddly convoluted method.

The CN2 only acts on the SWDIO/SWCLK pins. Review SB (Solder Bridge) usage on the board, look at user manual, and schematic contained therein. You'd want the make sure the local ST-LINK/F103 is disconnected from the target. See SWO and NRST

Check also for SB related to PA13/PA14 on the target