Hi Dear Colleagues,
My customer enabled secure boot on MPC5775E. Recently, their engineers tested the OTA feature, once the bootloader started to erase the app, they powered off the MCU. After that, they powered on the MCU again, the MCU started to run from the bootloader, but they found that the secure boot feature failed, CSE_SR[BOK] = 0 (normally CSE_SR[BOK] = 1, which means the secure boot is successful), according to the customer's strategy, it was not allowed for the bootloader to jump to app. By checking the registers of CSE, CSE_ECR[EC] = 0x0C (System memory error).
The customer downloaded a normal app(covers the region of bootloader and app) into the MCU, then downloaded the bootloader, used the bootloader to update the app, everything worked well.
In the customer engineer's understanding, if the OTA is interrupted, only the app is damaged, if they power on the MCU again, the bootloader should be able to update the app, but why the secure boot fails? How to prevent this issue?
