Thanks, I've tried and got a little bit further but now I'm stuck with that :
Selecting previously deselected package libslang2.
dpkg: regarding udebs/libslang2.udeb containing libslang2, pre-dependency problem:
libslang2 pre-depends on multiarch-support
multiarch-support is not installed.
dpkg: error processing udebs/libslang2.udeb (--unpack):
pre-dependency problem - not installing libslang2
Errors were encountered while processing:
udebs/libslang2.udeb
make[2]: *** [stamps/tree-unpack-netboot-stamp] Error 1
make[1]: *** [_build] Error 2
make: *** [build_netboot] Error 2
Regards