LFRAME isn't really needed to parse LPC-data and that's why modchips with an own LPC-implementation (X2, chameleon, ...) managed to find a solution so fast/easily for xbox v1.3. Cheapmods (SST chip) however use LFRAME and the LPC-implementation on these chips can't be modified. So it looks like the major reason Microsoft removed LFRAME was probably just to get rid of those cheap 'cheapmods'.

These people are now trying to enable cheapmods on v1.3 - they are not sure yet they will make it work, but they have a few good ideas on possible solutions.

Some sources also tell that a new MCPX will be released very soon in new xbox consoles, what will probably make the next xbox version alot harder to hack.