QUOTE(ldotsfan @ Jun 25 2008, 10:32 PM)

I'm also going to try booting the new hdd to an error 5 but power it from an external source and see if that starts the hdd into a ready state then reboot back to the old hdd and do the hotswapping later.
Eureka - powering the new hdd with an external source throughout the process and letting it boot first to an error 5 worked! After error 5 appeared, I unplugged the IDE cable and powered off the xbox. Then I reconnected to the old hdd and let the boot disc boot. This time, after the hotswapping, I was able to get the dash to boot up from DVD and do the hdd preparation on the new hdd.
So the error 5 does get the new hdd to a ready state. I'll be working on doing it from code as well.
The need for an external power source limits potential usage of this but if the IDE initialization from the XBE code works, then maybe no need for external power.
We are closer to the goal of a boot disc for softmod xbox to do hdd upgrade now.