MCU Reset via external watchdog timer while first time programming

[RV.4]

Hi,

We are facing some challenge with external watchdog timer and STM32H7855xi. when there is no program in flash input to external watch dog timer (WDI) is output and no pulse . during this time external watch dog timer continuously generate reset pulse to microprocessor pin (nRST which is default of pull up) .

when we trying to program through JLINK pro external watch dog timer not allowing to program , it continuously resetting the processor , we need to manually separate external watch dog timer reset pin from nRST pin by removing R69 as per given schematic.

Do you have any suggestion to avoid manual intervention 

[Tesla DeLorean]

You'd need to write loaders that will kick the watch dog. Perhaps use the system loader, push in code to RAM within the response window, and start executing that.