I saw that, here are the instructions also:
How to modify the Mac Classic for 4mb onboard as seen on Adrian's Digital Basement
** Remove two chips:
Remove UL1 CAS PAL (no longer needed!)
Remove UH6 74LS174 (no longer needed!)
** Modify system to think it has 4MB on the motherboard:
Pin 13 of UI4 BBU:
Remove R42 470ohm (under motherboard - this pulls pin to ground)
Pull up PIN 13 via 10K to 5V
(I did this by running a jumper between the left side of R42 and R41)
Pin 17 of UI4 BBU:
Should be pulled up to 5v already (verify but mine was already at 5v)
** Remove old 44256 RAM chips (8 of them, UK1-UK8)
** Install 4400 RAM chips (4x1mbit - I took these off a 4mb 72pin SIMM)
** Make connections to connect CAS lines from UI4 BBE to RAM:
Connect UL1 PIN 7 CAS0H to UL1 PIN 24 (CAS0H to UK1/3 DB8-14)
Connect UL1 PIN 6 CAS0L to UL1 PIN 25 (CAS0L to UK5/7 DB0-7)
Connect UI4 PIN 16 CAS1L to UL1 PIN 27 via 22ohm (CAS1L to UK6/7 DB0-7)
Connect UI4 PIN 19 CAS1H to UL1 PIN 26 via 22ohm (CAS1H to UK2/4 DB8-14)
(22ohm is just to make sure shorted DRAM doesn't kill the UI4 BBU)
Remove (optionally) and jumper over R43 and R56 (22ohm resistors) as these are in series with R3 and R19. This gives the CAS lines just 22 ohms (versus 44 ohms)
This replicates the Mac SE design exactly, in fact the Mac Classic is really a Mac SE... The UI4 BBU chip is the same one on the Mac SE, even though the part# is different, it seems to work in an identical way.