Everything you need to generate, build, and modify your own ramdisks for use with Zibri's exploit. Lex Utils includes 3 bash scripts, dmg2z, ramdiskstripper, and z2dmg.
You can download IPSW files on the IPSW section of this site.
Use the ramdiskstripper script to make a firmware 1.0-1.0.2 IPSW ramdisk dmg mountable. Edit the mountable dmg to your liking. Then use the dmg2z script to make it a ramdisk hack exploitable file. If you need to revert the ramdisk hack exploitable file you made back to a mountable dmg, use the z2dmg script.
Once you have your final ramdisk hack exploitable file, you can use the iPHUC zhack command to boot it if your on Mac OS X 10.4.10-10.9.5. See the iPHUC page for more information.