paulvha:
I think your code is overwritten the SVLThe Apollo3 can have 2 bootloaders: ASB and SVL.
The ASB loader is in ROM/OPT and is always started first. It can start loading a program from 0x0000C000 in flash.
When the SVL is used, it is loaded by the ASB from 0x0000C000 and occupies up to 0x00010000. So make sure your user program does not try to store there.
I am aware of ASB and SVL, and your guess should be correct. I also think I tried to overwrite SVL, which I don’t want to do, and perhaps that’s why it failed to flash the device. Thanks for the info; I will look into it.