programming • beebasm -di <template.ssd> : Problem reading from disc image, on macOS

I'm trying to get a half-reasonable Beeb development setup going on my Mac. I have beebasm assembling a program, and it will happily write it to an ssd image with or without the !BOOT file. The disc loads, boots fine the program run in JSBeeb and BeebEm. So far, so good.

Ultimately though, I want to develop a sideways ROM. I have the most simple service ROM assembling fine with beebasm, and I can *SRLOAD from the ssd it into sideways RAM on an emulated Master 128 and it's all good.

Now I'm trying to use the beebasm -di <filename> option which the beebasm documentation says "will use this disc image as a template for the new disc image, rather than creating a new blank one. This is useful if you have a BASIC loader which you want to run before your executable. Note this cannot be the same as the -do filename!"

I've made an ssd disc image using BeebEm which contains only the !BOOT file I want,
but when I try to use,
I always get,
with no further information.

Reading the relevant C++ source of beebasm, it's a call to is trying to read the first 512 bytes of the ssd file (the catalogue, I guess) and failing, but it doesn't try to elaborate on why.

What am I doing wrong? I feel like I'm missing something obvious. Do I have a sensible beebasm invocation?

Statistics: Posted by robert_smallshire — Mon Dec 01, 2025 9:25 am

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