The first change is to patch this code:
00fc0196 266E003E movea.l $3e(a6), a3
00fc019a B7FC00080000 cmpa.l #$80000, a3
00fc01a0 622C bhi.s $fc01ce.l
00fc01a2 B7FC00040000 cmpa.l #$40000, a3
00fc01a8 6524 bcs.s $fc01ce.l
This code reads the size of Chip RAM from execbase and checks that it is no greater than 512kiB ($80000) and no less than 256kiB ($40000). If the value is outside the expected range, a full reinitialisation occurs because it's assumed that execbase has become corrupted. This is the source of the bug where reset-proof RAM disks did not survive a reset on machines with more than 512kiB of Chip RAM. The patch changes the maximum expected size to 2MiB ($200000).
I'm not familiar with the code patched in the second change, but it updates the opcode of this instruction:
00feaf9c B0B900008000 cmp.l $8000.l, d0
... from B0B9 to B0BC:
00feaf9c B0BC00008000 cmp.l #$8000.l, d0
This is clearly fixing a bug where the wrong instruction was used because the value at location $8000 will be random and it makes much more sense to compare against a constant than a random number.