HP82143 Processor details

[brouhaha]

If the difference at the end is only in the bytes from addresses 0xfc0 through0xfff, it could be that your boric chip, his, or both, are actually MK3870/n2 chips, in which those addresses are extra RAM rather than ROM. The RAM is NOT mirrored at lower addresses on e.g. the MK3870/22.