So, the G2 is one of the top HTC Android devices at this point, and considered to be the successor to the G1 - the world's first available Android phone. As such, the G2 kind of has a special place in the vast array of Android phones, but as it turns out, it doesn't look like hackers are going to like the device.
After intense investigation and hackery by the hackers at xda developers, it was revealed that the G2 uses a special combination of hard and software to return the phone to its unrooted/unaltered state after a reboot when rooted/altered. At this point, the hackers aren't entirely sure if it's the hard or the software that does the trick. Basically, it appears that changes to the device's system software are intercepted and written to a special part of the flash memory without actually altering the system software.
"I think it is basically like an overlay. The underlying files are from a read-only
/system. Any changes get written to a separate place," mlevin explains, "It sounds like it is a lot like Sandboxie (a Windows app that lets you create safe sandboxes). Any writes to your disk or registry get intercepted at a low level and end up written to another location, which you can later delete to make it as if the files were never written. It's like a read-through cache but the writes don't go back to the underlying location."
The interesting thing here is that it's unclear who's fault this really is. You'd think HTC, but the Taiwanese phone maker claims it's either Google or the carrier who's to blame. "HTC is not aware of any Root Kit or Blocking feature on the G2. It is quite possible such a feature was added by Google or the Carrier," the company states.
It wouldn't surprise me in the least that this feature came from the carrier - which would mean the bulk of the "feature" consists of software (good news). Still, it's sad that once again, the device you buy is actually not yours.