I would, but everything now seems to be assembling fine on my Devpac 3 installation
On My A500 and then A1200, I originally had Devpac 2 and wrote a load of code, most never to be looked at again. When I upgraded my A500 to Kickstart 2.0.4, I upgraded to Devpac 3, specifically 3.04.
Last year, I restored my Amiga installation in WinUAE from the Quarterback backups of my physical A1200 and started looking through my old code.
There were a few different errors I had assembling Devpac 2 code in Devpac 3, but the most common one I can remember was code with "bset.b #<number_0_to_7>,<memory_address>" which failed to assemble with an error like "invalid size". I could fix it by altering my code to remove the .b as this is implied with the destination being a memory address anyway, but it assembled fine in vasm with the "-devpac" option enabled.
Since doing the restore, I have rebuilt my installation from scratch using the original ADF images of my own disks and had been working on resourcing GenAm to fix this, but hadn't actually tried assembling these things again until I was in a position to fix things.
Having just tried now, everything I tried assembled fine, I can only assume I had a rogue setting in my restored GenAm.opts file which resulted in the error message and the assembly failing. When I get a chance, I'll see if this fixes the other errors I was getting and I'll also restore my QB backup and compare the configurations to see what is different.