Revision as of 21:13, 7 April 2021

"Model T computer" system rom Y2K patches

General

All the KC-85 clones have the same routine holding the century digits, though appearing at different addresses in different system roms.

A Y2K patching rule that applies the same to all machines is to just search for a certain string of bytes wherever it happens to appear, and edit.

Using the hex-editor of your choice:

Search for this sequence:	`23 36 31 23 36 39`
Replace it with this:	`23 36 32 23 36 30`

0x5A53 0x31 -> 0x32

0x5A56 0x39 -> 0x30

0x5A5B 0x31 -> 0x32

0x5A5E 0x39 -> 0x30

0x575E 0x31 -> 0x32

0x5761 0x39 -> 0x30

NEC has a second place that must be edited in addition to the same rule as all the rest.

0x5D91 0x31 -> 0x32

0x5D94 0x39 -> 0x30

0x7E30 0x33 -> 0x31

0x7E31 0x38 -> 0x30

@@ Line 9: / Line 9: @@
 :{|
 |-
-| Search for this sequence: || <code>23 36 31 23 36 39</code>
+|style="text-align: right;| Search for this sequence: || <code>23 36 31 23 36 39</code>
 |-
-| Replace it with this: || <code>23 36 {{highlight|32}} 23 36 {{highlight|30}}</code>
+|style="text-align: right;| Replace it with this: || <code>23 36 {{highlight|32}} 23 36 {{highlight|30}}</code>
 |}