Readout protection only for Flash, not EEPROM possible?

[Schmid.M.]

Posted on January 24, 2018 at 15:19

Hi,

we are facing troubles with the readout Protection on the STM32L0: when you secure the chip and then want to do a firmware update, the Settings and serial numbers in EEPROM also are erased. Can we somehow protect the code without having a EEPROM erase with each firmware update?

Thanks,

Michael

#rdp #stm32-l0

[Tesla DeLorean]

Posted on January 24, 2018 at 15:29

Does chip have OTP you can use?

Have your update app query device before erase. 

[Schmid.M.]

Posted on January 24, 2018 at 15:38

No OTP available. Okay, so that means there is no option except for doing it manually or using external EEPROM for storing that stuff.

Could I do an update using an internal bootloader or would level 1 protection prevent that as well?

[Tesla DeLorean]

Posted on January 24, 2018 at 15:54

Your own firmware can read internals, the system loader is locked down and restricted. You could have your firmware write values in RAM location that is safe and check after mass erase.

Your own loader may also be able to selectively erase and write app sectors. Not probed L0 to that depth.

Also assuming you leave loader alone space at the end might be enough for serialization and calibration data.