The following table summarizes my understanding of the 128 ROM revisions for the United States. Version BASlo BAShi Kernal ------- ----- ----- ------ First 318018-02 318019-02 318020-03 Middle upgrade 318018-03 318019-03 318020-04 Final upgrade 318018-04 318019-04 318020-05 128DCR 318022-02 lo 318022-02 hi 318023-02 hi Part number 251913-01 is the 16K 64 OS ROM, which is present in both the 64C and the low-profile 128. I have confirmed that this ROM is identical to the first half of 318023-02. Also, I have confirmed that the final ROM upgrade is the same as the 128DCR version. The only difference is that the OS for the low-profile 128 is stored in four 16K x 8 ROMs rather than two 32K x 8 chips. -David Gahris dgahris@eece.maine.edu ------------------------------------------------------------------------------ I have a copy of an announcement from Commodore detailing the differences between the rev. 0 and rev. 1 ROMs, with part numbers, signature bytes, revision bytes, checksums and copyright dates. 252343-03 and 252343-04 fit neither the rev. 0 or the rev. 1 descriptions, but are half way between them. I have done a three way comparison of the ROMs. the results are summarized in the following table. rev. 0 252343-03 & 252343-04 rev. 1 copyright date 1985 1985 1986 ROM signature at 7FFC-D FFFF 5CAC 8DEF rev. byte at 7FFE 00 01 01 checksum at 7FFF 4C DC 61 ROM signature at BFFC-D FFFF E266 CDC8 rev. byte at BFFE 00 01 01 checksum at 3A 8A 5C ROM signature at CFFC-D FFFF AB16 8F76 rev. byte at CFFE 00 01 01 checksum at CFFF C3 BC 3C rev. byte at FF80 00 01 01 All changes in 252343 are also present in the rev. 1 roms. There are no changes in 252343 that are not in the rev. 1 ROMs. There are additional changes in the rev. 1 ROMs which are not present in 252434. There is one patch at FC44 that shows two stages of revision. The patch in 252343 has five bytes added in the rev. 1 ROM at the begining of the routine and the rest of the routine is move up in memory to make room for it. Five addresses in the kernal are therefore different in all three versions to accommodate the different versions of the patch. These ROMs were probably a test version of the rev. 1 ROM since they contain rev. 1 identification but do not conform to the announced rev. 1 checksums and signatures. -William M. Levak