32-bit acorn hardware • Re: RISC OS 3.20 ROMs?

So I'll ask again if you confirm that if you have ALL FOUR ROMs with blank upper halves, it still won't boot? Getting hold of 8bit ROMs this size isn't cheap for me to test/reproduce. I could possibly simulate your "bit of ROM" situation by 'mis'-programming a pair of 27C160s though.

Yes. With all four EPROMs, with blank upper halves (FF or 00), will not boot. The same thing happens with three RISC OS ROMs and an 8Mbit ROM.

Programming 8K of RO into the top of the second half makes it work fine. As does programming two copies i.e. making it so the top address line doesn't matter.

I think Timo might be onto something with the POST Box check idea...

Statistics: Posted by philpem — Sat Nov 15, 2025 3:34 am

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