ip.bin in 1st_read.bin Question

[Infinity_Engine]

Some selfboot games don't have an ip.bin, i mean its inserted in the 1st_read.bin as far as i know.
The problem is that when i try to re-make the cd (for different reasons) or make a nonboot game selfboot, i dont have the original ip.bin to insert into the 1st_read.bin.

For some games (like crazy taxi, power stone,etc) i used an ip.bin from another game and it worked just fine.

On the other hand other games didn't work, so i was wondering is
it because of not using the original ip.bin.