IBM PS/2 35 SX Hardware Maintenance Reference page 30

IBM PS/2 Model 35 SX, 35 LS, 35 SLC HMR
Memory Errors
3.3.3 Memory Errors
The system reallocates system-board memory in 1MB blocks for 1MB and 2MB
memory-module kits and in 4MB blocks for 4MB and 8MB memory-module kits.
If the POST detects a memory error in the first 1MB of system-board
memory, the entire 1MB of memory is deactivated and an error code is
displayed.
¦ Copyright IBM Corp. 1991, 1992
3.3.3 - 1