[GUIDE] HOW TO FIX your unflashable or soft bricked GSII - Galaxy S II Q&A, Help & Troubleshooting

Hello everyone!
I thought that this forum is more appropriate to post this, to avoid any new "lulz i r borked" threads. Plus, I had good feedback on the other flrum section
This is a guide dedicated to noobs, so if you're not one, I would advise to stop reading now! (altough feedback would be great! )
Yes, there have been quite a few threads about fixing a soft brick. But what I'm writting now is another solution to a different kind of problem : unflashable GSII (which also works with a soft brick of course ), which is a soft brick and a corrupted NAND rw (read/write) function.
Just in case you don't know, a soft brick occurs when you flash a ROM or Kernel, and it doesn't go your way, thus bricking the "soft part", aka Software, of your phone. Therefore, it is easy to recover from. Now, regarding NAND rw (NAND's read and write function being the corruption) it means that it is an issue deeper than a soft brick. It is obvious when you can flash a kernel, but you can't flash a ROM, because it can't properly read the NAND, but can flash a kernel. But you ask, why the kernel? Because flashing a kernel is a bit deeper than flashing a ROM. When you flash a kernel, you're changing/putting new instructions to the hardware, and when flashing a ROM, the instructions that are drewn are different and more "simple", so when flashing, ODIN wkll say "FAIL" instead of "PASS", or suddenly stopping the flash out of nowhere.
Let's start with the basic files, downloads and requirements​
1) You have to know the basics of ODIN and flashing (duh )
2) Just to be safe, please uninstall Samsung KIES. It usually interferes when flashing with ODIN. You must have the USB drivers from your phone, so don't uninstall them. Only uninstall the program KIES.
3) Download ODIN, the tool that we'll use to flash all the things into our beloved Galaxy S II
4) Download the necessary files : the Kernel, the Recovery Package and the Bootloader (it's the old one, which you can easily use a USB JIG to reset the counter and remove the yellow triangle when having a custom kernel or OS)
5) You must have WinRAR to unRAR the Recovery Package and to unzip ODIN.
You can also use 7zip, as sugested by jermitano
And that is it! Let's get down to business
If your GSII has the folowing symptoms :
Bootloop
Stuck on GSII logo, but already removed the battery to try to fix it
Enters Download mode and Recovery mode
It means that you are soft bricked and is easy to solve.
But if your symptoms are the mentioned above, PLUS the symptoms below
Enters Download mode but does NOT enter recovery mode (usually means a NAND rw corruption)
Doesn't flash
Bad flash in odin (FAIL after flashing, or the flashing suddenly stops)
Then it means that you have a bigger issue, such as the aforementioned NAND rw corruption.
It's time to open up ODIN and start reviving your phone!
First of all, let's just have a quick glance of how ODIN looks like, and where we should put the files :
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
As the picture clearly shows, the green rectangle is where you can tick. Those 2 which are ticked must remain that way.
ONLY FLASH WITH RE-PARTITION TICKED AND A PIT FILE IF YOU ARE SURE
THAT THE FLASH WILL SUCCEED.
Which means that you CANNOT have a damaged USB, corrupted drivers and such.
​
When recovering from a soft brick, it is recommended, not mandatory, to have Re-partition ticked with a .PIT file. So you must be extra careful when you are using a .PIT and Re-Partition. And obviously, the red box is the one where you can't and don't want to mess with
But where are the files going, you say?
.PIT -> PIT
CODE -> PDA
MODEM -> PHONE
CSC -> CSC
There is only 1 way to recover a soft bricked phone. How to recover from a NAND corruption? We'll get on that later on
Recovering a soft bricked phone​
1) Grab the Recovery Package, and you'll see a bunch of .tar files. Take a look at the names. You'll see CODE, MODEM, CSC and .PIT. Put each one in its place, and tick re-partition.
2) Turn off your phone. Enter Download mode by presing Vol. Up + Home + Power button.
3) Plug in your phone. It will show you, in a yellow box in ODIN, ID:COMx (x being the number displayed, sometimes displays 7, sometimes displays 9)
4) Once ready and done all your prayers, press Start. Wait patiently. It usually takes 5 minutes to flash.
Have you done everything correctly until now? Then...
Congratulations on recovering your phone!​
You deserve some cake afterwards, and some rest
Now, if your problem is the NAND rw coruption, and wasn't fixed by the above fix, then follow these steps :
5) Download the Kernel. Flash it in PDA. Without ticking Re-Partitioning
6) Successful? Nice, hope is still present.
7) Flash the recovery package, following steps 1-4 This should fix your issue. If it does not, then :
WARNING : FLASHING A BOOTLOADER IS DANGEROUS. FLASH WITH EXTREME CAUTION.
8) Download the Bootloader. Flash it as PDA or Bootloader in ODIN. Without ticking Re-Partitioning
9) Flash the Kernel, as in step 5
10) Flash the recovery package, like in steps 1-4 And that will fix any of your issues
I hope that this guide was helpful, and if it was, hit the thanks button!
Credits mainly go to Intratech, for his amazing gallery of ROMS and files
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Disclaimer
This is to be used as educational information. I am not liable of any damage that may occur to your phone.