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[Osborne] Dual BIOS ROM Daughterboard (2732->2764)

clueless_engineer (Brett)

Experienced Member
Joined
Nov 10, 2023
Messages
75
Location
Port Macquarie, Australia
Thanks to @nelgin making the alternative OZROM BIOS binary available from his machine, I designed a simple daughterboard so that both the original OCC BIOS and the OZROM BIOS can be installed at the same time, switchable via the A12 address pin.


Seems to work okay. The RAM tester identified a fault in bank B (4000-7FFF), 4th bit, so I apparently need to change the chip in location B24.

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