RemarksDisassembly of the Improved ZX81 ROM.
In error an EPROM was used with a modified COPY routine which drove a serial printer. A pink Errata slip was enclosed with the correct disassembly of COPY and notes on the Unimproved ROM.
Hueber Software re-released a disassembly of the 'Improved' ZX81 ROM with correct COPY routine (so no errata notes on Unimproved ROM), on ISBN 3-19-008206-5.