I've checked in a change for the sx1 200h that may fix some crashes. This will appear on the autobuild server, build 791 or later. Someone used nullsub from an FFC00000 base camera

Also, I've attached a test build for sx1 201a. Please note, I do not have an SX1 of any kind, so this is totally untested. It probably won't melt your camera, but it could easily crash. If you choose to try it, it's at your own risk.
edit:
added source patch.
edit:
and btw, to test 201a, I'd suggest downloading the full sx1 200h build from the autobuild server, and then replacing the diskboot.bin
edit:
oops, forgot to fix FlashParamsTable, updated