I have an iMX chip and I am trying to store a few bytes of permanent information on it so that repeated flashes of a unit will still retain this information (i.e. serial number, etc.).
I have successfully been able to fuse some of the OCOPT (On-Chip One Time Programmable) registers (aka eFuses), however I am running across an issue where the mfg tool will not work correctly when some of these OCOTP registers are modified.
In full, I was trying to use CFG4, 5, and 6 registers to store my information. I also tried using ANA2, and GP1 and 2 (these were on different iMX chips though, so trust that only CFG4-6 were changed on a working chip). I was a bit surprised in that some registers already had been fused (i.e. CFG0-3 and ANA1).
I am trying to understand why the mfg tool wouldn't work given that I modified these eFuses.