Recovery a MPC55xx with erased shadow

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Recovery a MPC55xx with erased shadow

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gmgunderground
Contributor II

Hi to everyone, I have a MPC5554 with an erased shadow block, but code inside Flash and externa EEPROM is OK, I have checked it before turning off the board. Now my question is: is there some way to execute again code inside internal flash so I can program again the shadow (the application in flash has the routines to execute a RAM code)? BootCFG0 and BootCFG1 are both  LOW, so as described in de datasheet the CPU has to execute FLASH application, but it doesn't.

 

After some tests, now I'm able to connect to MPC5554 with CAN Seria Boot. If I write an application to download to RAM can I recover my SHADOW or it's time lost?

 

Best regards

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lukaszadrapa
NXP TechSupport
NXP TechSupport

Hi all,

this issue was discussed also via Service Request, so I will just summarize it here for others:

- the device was locked because there was alignment error during programming of shadow flash. Shadow flash was correctly erased but the program operation did not pass due to alignment of data. When using SSD flash drivers from Freescale, it is necessary to align destination address and size to double word, source address must be aligned to word.

- user's code in flash will work even if device is locked. If it doesn't work, there's another problem not related to censorship.

- it is not possible to unlock the device using serial boot. Internal flash is disabled during serial boot.

- the device can be unlocked (talking about situation when the shadow flash is erased or when we don't know the password) only when the code that is already programmed in internal flash provides some option how to recover the shadow flash.

- and there's also application note that describes how to prevent device lockout:

http://www.freescale.com/files/32bit/doc/app_note/AN3787.pdf

Regards,

Lukas