Be rooted. Have a computer with adb working, or do this from an android terminal emulator. The instructions are for adb.
The applypatch commands are going to have [] around them to show you what to put, but we not used in the actualy script.
----------------------------------------------------------------- -----------------------------------------------------------------
A = Desired Boot.img's Sha-1 sum
B = Size (in bytes) of the desired boot.img
C = Original Boot.img's Sha-1sum
Looking at the updater-script you can see this line of code or something similar for applying the boot.img.p to the phone's boot.img.
You need this as a reference for the SHA-1 sums of the patch and boot.img and desired final boot.img.
//Reference script\\
//Actual script\\
Actual commands used to patch D4 .219 fastboot file boot.img with D4 6.16.208 boot.img.p:
------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------adb shell
su
cd sdcard-ext
applypatch boot219.img boot208.img 4a7070c32d0312aa48e52e207c7932434bc46cb1 8388608 fe086e1f547082c3cf2a5f65dacb81fd232ecd89:boot208.img.p