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Reflashing the bootloader firmware from ST



I am working with Nucleo-H743ZI2. Using ST Programmer I did full chip erase with Read protection option bytes as CC. Now am getting an error message cannot find STM32 target. I guess I have to reflash my basic firmware packages from ST but I am not aware how to do it since am using ST nucleo board newly. Any suggestions would be appreciated thanks in advance. 

Principal III

dont play around with read protection !  first read rm , what it will do...





so - if you set CC -> need new chip or board, if you cannot desolder old/solder new.


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Lead II

Hello @Freshna 

Setting the RDP (Read protection) to 0xCC means you have activated the RDP Level 2: 

  • When the global read protection level 2 is set, the below rules apply:
  • All debugging features are disabled.
  • Like level 0, all read/write/erase operations from/to the user flash memory are allowed since the debugger and the boot from RAM and System flash memory are disabled. Accesses to the other secured regions are also allowed.
  • Booting from RAM is no more allowed.
  • The user option bits described in Section 4.4 can no longer be changed except for the SWAP bit.
  • Caution: Memory read protection level 2 is an irreversible operation. When level 2 is activated, the level of protection cannot be changed back to level 0 or level 1.
  • Note: The JTAG port is permanently disabled when level 2 is active (acting as a JTAG fuse). As a consequence, STMicroelectronics is not able to perform analysis on defective parts on which the level 2 protection has been set.Apply a power-on reset if the global read protection level 2 is set while the debugger is still connected. (According to the part 4.5.3 of the RM0433).

Then is going to be impossible to reduce the protection level. 



That's why you need a new board now since this board is locked.

best regards.



The ST Boot Loader is in OTP/ROM, you can't erase it or replace it.

You could try adding a jumper to connect BOOT0/VDD this would perhaps allow for connectivity in the case the MCU is getting into the wrong mode via user code. It will not fix Option Byte issues, especially if you disabled SWD/JTAG connectivity, as RDP 2 is non-reversible. 

Tips, buy me a coffee, or three.. PayPal Venmo Up vote any posts that you find helpful, it shows what's working..

Is there any possible way for me to use this board without using flash memory

yes, the onboard st-link you can ( by using the jumpers..see manual) use as tool to program any other STM32 chip.

but this H743 is just useless now.

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This  MCU is useless. You need to use a new one.

Best regards.