Sorry for being late reply. Was kinda busy.
Ok, Im still a noob but I will explain here how and what precautions I took so please bare with me and sorry for my bad english.
First, download the guides from here:
http://www.infinitymod.com/download.html (MG2 Section)
You can get all the details for MG2. I didnt use the software provided but instead I use Jrunner. (I hate all the Dos command stuffs

)
JRunner -
http://bit.ly/K8z3OPOnce you got all the guides and Jrunner, you are good to go.
As far as I know, PHAT are kind of "sensitive" cos of theres 2 PHAT I didnt handle properly, its turned to 3ROD. The best way to do it (based on my experience) is soldered the Matrix SPI Nand flasher first (Im assuming you are using Matrix SPI Nand flasher cos Im using one

. Dont do other thing, just solder the wires or you can as well solder the MG2). Then Test the PHAT and see if it will operate normally by booting it. Dont have to reach the menu, once you see the XBOX logo you can switch it off cos to prevent over heating else you will get 3ROD

(the internal fan need to be installed in order for the PHAT to boot and best when you boot the PHAT, try place the fan on top of the heat sink).
Use RCA cables instead of HDMI. (Thats what I was told to do so)
If PHAT boots normally, off it then proceed to Jrunner. (Im assuming you have the drivers for Matrix SPI Nand Flasher installed properly or any Nand Flasher you are using.)
http://i1078.photobucket.com/albums/w49 ... runner.pngSelect Falcon in "NAND TYPE".
In "CoolRunner Programming", select "USB".
Then "READ NAND".
It will read the nand twice. Just wait. Once done, Jrunner will give out a notify sound (Kinda impressed).
Then "Create ECC" and "Write ECC" (nothing to do much here, just click the buttons).
Now, solder the MG2 to PHAT (You can solder first after you solder the nand flasher before reading nand, either way its ok).
Please take note on the wiring (the length):
A= CPU_RST (55cm)
B= POST_OUT (25cm)
C= STBY_CLK (any)
D= I2C_SDA (not used)
E= I2C_SCL (not used)
F= PLL_BYPASS (22cm)
GND = (any)
VCC = (any)
(any) as in any length will do. A, B and F need to put into consideration.
Here is how I solder:
Always remember: Cleanliness is a virtue. (Did I say it correctly? Whatever! Just make sure your soldering points a CLEAN! I seen alot of the pics around, the soldering points are "dirty"

)
Dont solder your GND to the metal of the USB port but solder to the metal of the Display port instead. (Im not sure this make a diff but it did make a diff for me. When I solder to the metal on the USB port, nothing happens at all, not even blue light flashing. Once I change back to the metal on the display port, theres light

doesnt really makes sense to me for both metal are ground. It did worked for me so I decided to mention it)
Please take every small details into consideration. They DO make changes. Dont ignore!
http://i1078.photobucket.com/albums/w49 ... G_0663.jpghttp://i1078.photobucket.com/albums/w49 ... G_0664.jpghttp://i1078.photobucket.com/albums/w49 ... G_0665.jpghttp://i1078.photobucket.com/albums/w49 ... G_0668.jpghttp://i1078.photobucket.com/albums/w49 ... G_0669.jpgOnce solder work is done, boot your PHAT. Xell should boot up and you should be able to get your CPU key. (Im assuming your PHAT motherboard is totally "naked", not in metal casing or anything and make sure your motherboard is sitting on some insulating material eg, plastic etc.)
If nothing happens, off it and boot again. If still nothing happens, connect the motherboard back to your pc via Nand flasher and write back your original nand using Jrunner "WRITE NAND". Boot it again and see if you get the xbox logo. I got 3ROD on first try due to poor handling. If you get 3ROD, then you need to reheat the xbox CPU and GPU (I hate it, really troublesome

). If it boots normally, then proceed again the steps until you get Xell boots up. Most importantly, make sure your soldering isnt short circuit and correct wire length. Everything should be fine.
Once you got your CPU key, copy it and paste it into JRunner "CPU KEY".
Select your dash version in "XeBuild Options". Normally its blank, just add in 15574 (I use this version and make sure you are connected to the internet).
Select "Glitch" and "RGH".
Then "CREATE IMAGE".
Now, go to your Jrunner "output" folder. If you get a file updflash.bin, rename it to nandflash.bin. Copy this file into a pendrive (make sure its not in any folder) and make sure xenon.elf file exist together along with nandflash.bin. Attach to your PHAT and reboot your PHAT. Xell should be able to boot up and let it do its job.
You should get a black screen with white words in a matter of seconds once Xell is completely boot up. Wait till it say something like "power off set and reboot" (I cant really remember that part lmao).
Reboot your PHAT and wala~! Your PHAT is GLITCHED~!!!
Once again, I need to remind you, PHAT is more "sensitive" than SLIM. So please handle with care.
Hope my guide helps and please dont hesitate to ask if you got any questions.
Thanks to S4BRE, Jaggahax, nice69 and whoever I forgotten. They are the one who guides me

Thank you!
PS- Im sorry, a week ago when I done this, there isnt an upgrade for MG2. My method is the "old" way.