After unpacking by:
HDR=`binoffset bzImage 0x1f 0x8b 0x08 0x0`
dd if=bzImage bs=1 skip=$HDR | zcat - > kernel.unpack
(binoffset.c is in sources of Linux).
strings kernel.unpack | grep 070701
Gives the listing of archive. Just after the entry for /init in
strings kernel.unpack | less
Is the contents of script.
It is not perfect solution but at least it seems to work. Please answer if you know 'correct' way (for binaries) easy (not writing long program) - I'm not marking it as solution.