[U-Boot-Users] 83xx address translation: is it really necessary?

I'm adding support for a new 83xx board, the 8349E-mITX. For some reason, turning on address translation causes the board to halt.

enable_addr_trans: /* enable address translation */ mfmsr r5 ori r5, r5, (MSR_IR | MSR_DR) mtmsr r5 isync blr

As soon as the mtmsr is executed, everything stops.

So for now, I've disabled the call to enable_addr_trans(). I know I need to fix this bug, but my question is: why do we enable address translation at all? My U-Boot works perfectly fine with it turned off, so what's the point? U-Boot 1.1.3 didn't have this "feature".