We use STM32L051C8T6 for mass production.STM32 has been programmed with an hex files. But it was found be locked and we cannot upload new files into them. Who know to unlock the chips?? Urgent!!!

[Shullen]

We are right now using this MCU STM32L051C8T6 in a mass production up to 32.000 sets

Right now we have met a problem,afer all 32000 pcs have been programmed with an hex file.I was found mcu have been locked and we cannot upload new files into them.

1. Can anyone help to figure out why the MCU was locked after the programming?

2. Is there any solutions to unlock the MCU which has already been soldered on the PCB boards?

Thanks!!

[Bob S]

I don't know the L0xx family, but in general:

How are they locked? Is RDP set to level 2? If so, you are out of lock as that cannot be un-done. If RDP is level 1 then you should be able to reset to level 0.

If RDP is level 0, are any of the sectors write protected?

As to why they were locked after programming - that is anyone's guess. Did your company program them once, and now cannot re-program then? Or did someone else program them and then send them to you?

[Tesla DeLorean]

Locking in production would seem like "normal operating procedure" to protect the client IP. Unless you've provided them with specific instructions to the contrary, I'd expect security fuses or the like to be blown after programming and verification steps.

Level 1 Readout-Protection would require you connecting and Mass Erasing the part.

Not clear what methods of connectivity your design provides.

Level 2 is irreversible, purposely so. At that point whatever update methods you have within your own code should work. Might not if you've not tested them in this mode.