So last night I decided to upgrade to 173 after reading all of the positive reviews on the leaked version. I was on 748 running in Infex with great satisfaction so it was a pretty big decision for me to want to upgrade the OS. This is what I did: 1) Disabled Safe Mode in Safestrap 2) Wiped cache and Dalvic cache (I didn't do a factory reset) 3) Flashed 744 via RSD lite 4) Re-rooted using Doomlord v3 5) Used Voodoo to temporarily unroot 6) OTA to 748 7) Checked to see if Voodoo retained root (it did and I temporarily rerooted) 8) Flashed 173 via stock recovery What suprised me is that when I was back to 744, all of my non-rooted customizations were still there; I thought that the fastboot file would return the phone to an out-of-box stock state like an sbf (which is why I didn't do a factory reset in the first place). It was like upgrading down to 744 (the way that OTA upgrades retain customizations). I've used sbf's on my Droid X a few times so I was suprised to see that the same thing didn't happen with the fastboot file. So I have a couple of questions: 1) What is the inherit difference between sbf and fastboot files (i.e. how are they used differently)? 2) Was it just stupid random chance that everything updated to 173 without a hitch since I didn't do a factory reset from the onset? Thanks in advance for your time.