After much battling, and courtesy of some recently uploaded patch files, i've got FreeBSD8 working on the plug.
However, upon trying to set up ports using portsnap - which fails consistently but at varying places in the untar, i've now also got errors unzipping the port.tar.gz:
splug# fetch ftp://ftp.freebsd.org/pub/FreeBSD/ports/ports/ports.tar.gz
splug# gunzip ports.tar.gz
gunzip: invalid compressed data--crc error
gunzip: ports.tar.gz: uncompress failed
the same file extracts fine on an i386 machine.
Has anybody got any ideas how to debug this?