Hi!
Let's say that i have a v1.4 or v1.5 xbox,
would i be able to swap motherboard in those with ones from v1.2 or v1.3 then?

Ie replace the current motherboard in a v1.5 xbox with a v1.2 motherboard.

I can't find a reason to why it shouldn't work

The only reason i could find to it not working is if there's diffrent connections from the case to the motherboard between the cases, i suppose they all have the same layout and cables?

Well apparently a 1.4 looks like a 1.3 - therefore connections are the same- so it should work.

But not older ones as they had a different PSU connector

Oh - remember the HDD is locked to the mobo

HTH