Sorry, meant "the chip" not "htchip". And as for the other stuff; I use Evolution-X. Which leaves my original xboxdash untouched. So for me, de-activating the chip will at least let me see if everything else is working. I didn't have anyway of knowing if you did the same thing. If you had, then de-activating would have been a good way to start troubleshooting your problem. But if you are freezing the box at the "X" screen then I don't know what to say at this point other than what follows is useless if the whole box freezes.
If you just had a blank screen but the box was still working you can try to change a setting in the config.xml file for Mediaplayer. You will need to FTP to your Xbox. Navigate to the partition where you have your Mediaplayer installed. Download the config.xml file from Mediaplayer partition.
Scroll down your config.xml file until you see this part:
"
<resolution>1</resolution>"
If, and I say IF, you can FTP and grab the config.xml file, see if the value positioned between "<resolution>[value]</resolution>" is anything but 4 or 5. If it is, change it to what it should be, or what you think it should be. If you have a value of 1 I believe that means it tries using the Xbox Bios default setting. After changing the value, upload it back into the Xbox and restart the Xbox. See if that does it. If not, try the other value using the same method. Also double check that your new value was indeed uploaded from the last attempt. You should be prompted about wishing to overwrite the file. You should choose "yes".
Also, if need be, (if you can FTP and none of that works) you could FTP your saved files from the original Xbox back onto the hard drive to see if the box works using the original settings and *.ini file, with the chip deactivated. I'm assuming you backed up those files before modding the box.
Again, all that is useless if you can't FTP to or from the Xbox. If your drive is locked then it'll be real hard to stick the drive into a PC to fix the problem. There is some information elsewhere for unlocking a hard drive outside of the box. If it is unlocked, then you could stick it in a PC and navigate to the config.xml and try changing the values. Though time consuming that may be the only way if you cannot FTP to the Xbox.
I hope all this helps.