There needs to be a MCFG_80186_IRQ_SLAVE_ACK so the cpu can callback the pic ack line but if the pic isn't even being configured then that won't be the source of the current problem. Is the boot floppy image at bitsavers somewhere?
I'm using the CTOS init image from /bits/Convergent/ngen/5_imd_set2. There's also a B26 BTOS Standalone disk set in another folder (The B26 is the Burroughs equivalent of the NGEN CP-001, should be pretty much the same hardware). I have tried fiddling with the 80186 IRQ_SLAVE_ACK a bit, but I'm not at all familiar with the 80186.
