The X2 BIOS 4977 and 4978, and may their other ones, will NOT boot from CD if something is wrong with your xboxs' HDD. Y has Team XECUTER not addressed this.
I have an issue where I screwed up my HDD with fonts exploits, then tried to repair with Chameleon. I finally found a post that mentioned that the X2 BIOS will not boot the CD if there is something wrong with the dash. The post said to try EvoxD.6, and that has done it for me.
With team Xecuter keeping there BIOS up to date, it would be a GREAT service if they added this feature for those fools who manage to screw up their xbox HDD.
Note: Dont wana complain about X2 BIOS and be using a Chameleon chip, not that it matters. System Mods were sold out of X2 Lite+ at the time and I wanted to fix this as soon a possible, kinda worked out, because I would have been one of those dopes who tried to flash an X2 with the new X2.4978.
Which goes to show you, CHECK the specs first and if it is NOT something you need, or you are NOT having probs, then DO NOT FLASH THE BIOS.