I want to update the bootloader in the flash area from 0xE000 to 0xFFFF of the MC9S12DP512. The guys before me had protected this area by programming the FPROT register to 0xD7. To update this bootloader I have a program for maintenance running in RAM. It has to erase this flash area and write the new booloader. But with the protection in the FPROT register, this flash area cannot be erased.
Does someone know how to reset the FPROT register to 0xFF to unlock the flash area or how to mass erase the whole flash if needed. I don't mind what is in the flash memory of the MCU, everything can be erased. I have set the FPROT to 0xFF in my maintenance program but it does not change.
I don't have USBDM but only a serial line RS232 to upload the maintenance program into RAM.
Let me know if you need more information.
Thanks a lot