Saturn Swap and BootDisk

This is odd....

Between me and my friend we have four saturns one is a mark 1 the other three are mark 2s , All have different mother boards and laser units.

The mark 1 and one of the mark 2s will do the swap trick every time (These two are mine). The other two mark 2's (My Mates) will not do the swap trick at all for games, but one of them will boot the bootdisk doing the swap trick, i have modified the door switch so we can open and close the door by using an spdt switch. This is where the problem arises we can boot these games which are cdr back ups:


Capcom Gens 1-5

Night warriors

Marvel super heroes

Steam Hearts

Radient Silvergun

Metal slug

Etc Etc

Notice a pattern?

They are all made by 3rd party computer game companies NOT Sega

Any other game like Shining force 3 Parts 1-3, or Bug 2 etc will not boot as they are produced or published by Sega (We think!)

Any advice would be great and any more information needed just ask.
I don't know how much help i can be but i've also had great troubles with this stupid swap trick, i have a model 2 and i have booted sega rally with the swap trick but only with the original cd that i burnt it from as the bootcd which negates the point of burning and swapping, which also brings me to the question, what about the iso's of games that I've donloaded, how am i gonna boot them with the swap method without the original....alternativly does anyone know a place in australia that might stock saturn mod chips ???
Um both the saturn mark 2's in question dont actually work with the mod chip either. I have tried them out and the mod chip works with the other mark 2 i own.