Obtaining IMG3 Keys

This is one way of getting the IMG3 keys using iBoot/iBEC patch based on the Dev Team's and Geohot's exploits.

This method is tested on both Linux and Windows OS.

Epic thanks to #xpwn crew on irc.osx86.hu !

What you need

1. Pwned 1st gen iPhone on 1.1.4 OS
   
2. ibooter from here [1]
   
3. iBEC.m68ap.RELEASE.dfu from iPhone1,1_1.1.4_4A102_Restore.ipsw
   
4. xpwntool from [2]
   
5. iPhuc (for Windows users only)
   
6. Any Hex Editor
   

Summary

Patched a function in the iBEC file so that it will branch to the desired memory location when the associated iboot command is called in ibooter. The desired memory location is at 0x09000000 as indicated by an earlier Geohot post and the iboot command chosen is "clearenv" in this documentation. The desired memory location will be housing the codes that enable and call the hardware aes engine so that the KBAG data can be decrypted for Keys/IV.

Steps

Unpack iBEC.m68ap.RELEASE.dfu

Utilizing xpwntool, enter this command:

xpwntool <original iBEC file> <unpacked iBEC file>
i.e.
xpwntool iBEC.m68ap.RELEASE.dfu unpacked_iBEC

Patching iBEC.m68ap.RELEASE.dfu

Before:

ROM:180074A0                 PUSH    {R4,R5,R7,LR} ;"clearenv" routine starts here
ROM:180074A2                 ADD     R7, SP, #8
ROM:180074A4                 ADDS    R4, R1, #0
ROM:180074A6                 CMP     R0, #1
ROM:180074A8                 BGT     loc_180074B4
ROM:180074AA                 LDR     R0, =aNotEnoughArgum

After:

ROM:180074A0                 LDR     R3, =0x9000000
ROM:180074A2                 BX      R3
ROM:180074A2 ; ---------------------------------------------------------------------------
ROM:180074A4 dword_180074A4  DCD 0x9000000           ; DATA XREF: ROM:180074A0�r
ROM:180074A8 ; ---------------------------------------------------------------------------
ROM:180074A8                 BGT     loc_180074B4
ROM:180074AA                 LDR     R0, =aNotEnoughArgum 

You will notice that iBEC starts at 0x18000000 but in your Hex Editor, just do the following changes at 0x74A0:

0x000074A0: 00 4b 18 47 00 00 00 09

The idea is to tell clearenv routine to branch to 0x09000000 and BX is used because the codes to be used at 0x09000000 later will be in ARM. This "clearenv" routine is in THUMB mode. BX will enable them to switch. Save and name your modified iBEC, for example iBECmod.

Packing the modified iBEC

Using xpwntool:

xpwntool iBECmod iBEC.patch -t iBEC.m68ap.RELEASE.dfu

Note that the original iBEC file has to be used after -t as a template. IBEC.patch will be your modified, packed iBEC file.

Executing patched iBEC in ibooter

Windows

Put iPHUC and your patched iBEC in the same folder. Boot iPHUC and boot your iPhone in recovery mode. Type the following into iPHUC once it recognizes your iPhone:

filecopytophone iBEC.patch

It should return "filecopytophone: 0"
Then type this:

cmd go

Your iPhone will reboot and display a blank black screen immediately.

From here, open iBooter and type

Linux

Put your iPhone in recovery mode, connect the USB cable and launch ibooter. Press ^F (CTRL+F) and Enter, you will be prompted for a file name, type and patched iBEC file name and press enter. Next you will be prompted for memory location to load. Enter 0x9000000 for that and press enter.

Now type:

go

to execute the patched iBEC. Your iPhone will reboot into a blank screen and that's good. You need to reconnect the ibooter after the "reboot".