JTAG debugging of boot sequence?


I am working on some software that will reside in the boot-loader in
different ARM systems. Part of the software needs to interact with the
MMU (enabling/disabling/modifying and creating translation tables).
Since this is more or less impossible to test in a running system, I
am now looking for some kind of development board that will let me
debug the boot-sequence. What I had in mind was some kind of
development board and debug solution that will let me stop the boot-
loader right before the linux kernel decompression, where I plan to
insert my software for testing purposes.

So, what do I need? Will a BeagleBoard with JTAG work when debugging
MMU operations (I will need to disable the MMU for a while)? If so,
what sort of equipment and software do I need?

Best regards,