I had the same problem (Illegal Instruction) when testing with OS 7.6.1 and OS 8.6.
Then I compared the patched driver with the original and noticed that one value was set to 0x4E 0x17 instead of 0x4E 0x71.
The former is an illegal instruction the latter is a nop.
So I changed the 0x17 to 0x71...