One of the major questions that common iPhone users, especially the ones relying on baseband unlock, would ask is the difference between old bootrom and new bootrom and MC & non-MC models. It’s important as many of jailbreak and unlock tools rely on this and most of the times, MC-models or iPhone with new bootrom are left alone, this is just what happened with latest PwnageTool 4.0 release.
So, here is how to check iPhone bootrom:
Windows
Step 1: Put iPhone in DFU mode and plug it into computer via USB
Step 2: Go to Windows “Device Manager” (Right click “My Computer”, then go to Properties > Hardware tab >Device Manager
Step 3: Look for your USB devices under “Universal Bus Controller” section in Device Manager
You will find a USB device attached with name “Apple Mobile Device USB Driver”.
Step 4: Right click “Apple Mobile Device USB Driver” and select “Properties” from right click menu.
Step 5: Go to “Details” tab and look for “Device Instance ID”
Step 6: Scroll through till you find iBoot (bootrom version)
Step 7: 359.3 = Old bootrom 359.3.2 = New Bootrom
Mac
Step 1: Put iPhone in DFU mode and plug it into computer via USB
Step 2: Open “System Profiler”, go to “Hardware” tab and select USB menu on left.
Step 3: Go to “USB Device Tree Panel” > “Apple Mobile Device (DFU Mode)”.
Step 4: Find “String on Serial Number” in upper right section of the information presented.
Step 5: You should find bootrom version (iBoot) at the bottom.
Step 6: 359.3 means its old bootrom & 359.3.2 means new bootrom
Without Connecting to Computer
Step 1: On your iPhone, go to Settings>General and tap on “About”.
Step 2: Information about your iPhone will show up.
Step 3: Look for “Model” in the list. If your iPhone model number starts with “MC”, then you’ve got new bootrom (MC model), if it doesn’t start with “MC”, you’ve got old bootrom (non-MC model).
You can also see other useful information there, like your iPhone baseband version, serial number and more. Full list of information shown is given here.
mohammad 
