RDP Level 1->0: Can ANYTHING survive ??

[Goof Ball]

I am using STMCubeProgrammer in USB DFU mode to change from RDP Level 1 to 0 (using command line -rdu option). This nukes (mass erases) all flash and all "backup SRAM" (according to datasheet).

My product has a couple of bytes of custom config data stored in flash, which of course gets nuked. Is there ANY way to save this config data, such that I can put it back into flash after I'm done changing RDP to 0?

I tried:

• writing my config data to known location in regular sram, then jump to DFU mode, then use STMCubeProgrammer to change rdp 1->0, then read the SRAM. But that gets nuked too, either by the bootloader, or hardware when rdp1->0.

[Tesla DeLorean]

Doesn't it have 528 bytes of OTP situated at 0x1FFF7800- 7A0F ??

[Goof Ball]

Yes, but alas, the configuration data changes once in a while.... thus the "one-time" aspect of OTP is a problem. Good guess though... I suppose if my config data changed once per month, my product would run for 16 months (OTP divided into 16 blocks) before crapping out. Any other ideas?