I did the same thing with factory resetting a few months ago,and was surprised that it didn't take it off,but my phone wasn't showing the super user app.So I went threw the steps of rerooting so the superuser app would show up again,and definitively not going to unroot the phone cause I like customizing the phone too much and looking for new customization's,even at work,lol.
Well Im fairly new to android so I dont know if EVERY phone has an sbf option. But its pretty much a factory reset, only it wipes the phone completely and installs a fresh os on it. At least thats what I think the process does. Its more of a complete wipe and reload than the normal factory reset is. Its mainly used to get your phone up and running again if you are having problems booting it up or whatever. It requires files and programs on your computer to do it. I just learned about it in my root experience with my phone.
Do the following steps to perform a Factory/Hard Reset on your Samsung Infuse 4G:
Step 1. Go to your Samsung Infuse 4G Home screen.
Step 2. Tap .
Step 3. Tap Settings.
Step 4. Tap Privacy.
Step 5. Tap Factory data reset.
Step 6. Tap Reset phone.
Step 7. At the confirmation screen, tap Erase everything.
Step 8. Your Samsung Infuse 4G will reset to the factory default settings automatically and when finished, displays the Home screen.
Note: Performing a Factory data reset will erase all data from your Samsung Infuse 4G and internal SD card, including your Google account, system and application data and settings, and downloaded applications.
It will not erase current system software, bundled applications, and external SD card files such as music and photos.
Thats actually not a hard reset. Thats just a factory reset. The hard reset is when you turn the phone off, (pull the battery out if phone is froze) then turn phone on, while the phone is turning on, hold the volume up button, home button, and power button all at the same time. Then follow the on screen instructions, its pretty easy.
With my Motorola or perhaps it's the Verizon phones, a factory reset certainly does remove root access. It also removes the superUser.apk from the system/app. However, the phone still has the flag enabled to indicate that is has been rooted in the past, to void any warranties. They're playing dirty!
On the plus side, I had removed a lot of bloat from the system/app folder before performing the reset and those were not restored. For anyone who accidentally removed the wrong app though and looking for a cure all, this will not help.