Same thing just started happening my my v.1.0 xbox with matrix chip. Started getting the error 5 code, so I figured it was trying to load the default bios and balking due to the unlocked after-market HDD. Now here's the weird thing: I pulled the mod chip and carefully read throught the developer's kit manual. Double-checked the dip switches and re-seated the matrix - all the appropriate LED's depending upon the dip switch settings. I've set the switches so the matrix loads by default; however, the default stock bios loads everytime. Of course, the good news is at least I'm not getting the error 5 code and we can still use the xbox, just not all the features allowed with the mod. If the mod chip is shot, how is it possible for the stock bios to load with the aftermarket HDD?