I'm compiling without thumb. I'm using gcc-4.7 which could do thumb. I'm not yet signing packages. You should not install busybox on scratchbox. You don't need it on sdk, as there are full coreutils.
dpkg: regarding .../base-files_7.1_armel.deb containing base-files: package uses Breaks; not supported in this dpkg dpkg: error processing /var/cache/apt/archives/base-files_7.1_armel.deb (--unpack): unsupported dependency problem - not installing base-files Errors were encountered while processing: /var/cache/apt/archives/base-files_7.1_armel.deb E: Sub-process /scratchbox/devkits/debian-etch/bin/dpkg returned an error code (1)
echo "/lib/arm-linux-gnueabi/ /usr/lib/arm-linux-gnueabi/ \ " >> /etc/ld.so.conf
cd /usr/lib/libfakeroot/ ln -s libfakeroot-tcp.so libfakeroot-tcp.so.0
unset SBOX_REDIRECT_FROM_DIRS export PATH="/bin:/usr/bin/:$PATH"
fakeroot apt-get install libc6 fakeroot apt-get install dpkg fakeroot apt-get upgrade fakeroot apt-get dist-upgrade