... I think I have already accommodate
this by using the latest gdb and cross-compiling it and it starts up

in

architecture powerpc:common.
...

Charles

Last May I was trying to get gdb/kgdb working over a link from an i686
host to an MPC8541 target. At the time I had exactly your problem, and
the solution that worked for me was what I told you. It looks as if gdb
has moved on since then, but if you wish I can send you (off list) the
build of gdb that worked for me, and for which I needed to set
architecture to powerpc:common.

Another thing I did fairly early on was to abandon a serial connection
in favour of ethernet, and using:

(gdb) target remote udp:<ipaddress>:6443

but that probably makes no difference to the problem.

Clive