Can't get past Boot Load - Simple solution

I have done, on three S3's now, the same mistake that many have probably done, especially according to all the threads on various sites I have seen. And whatever that mistake is - I still don't know what I have done to cause it - none of the solutions actually work.

I am refering to Bricking my phone, or partially. In my case the phone won't boot properly and will not get past the Samsung logo

The problem I found with all the other threads and solutions is that they all assume:

1. You can access the phone via a PC, but as you can't boot the PC drivers do not install and it is not recognised, so Odin, and the fantastic Android Toolkit do not work
2. They are very complicated or even very risky.
3. And I have yet to find one that works.

I am not an engineer or Android, or any other type of programmer - at all. I simply follow instructions, so whatever I did had to be simple. :)

So I fixed my S3 and I am sure this will work with ANY device, S3, S4, S5, Sx???? or make. It did assume a second working model and that the phone could at least read a SD Card.

1. I simply booted my working S3 in to Recovery, in my case TWRP
2. Made a backup by going in to "Backup" but JUST selected the "BOOT" Partition (I did notice the EFS option too, and that is another problem users have - another day)
3. "Swipe to Back Up"
4. I then used "Advanced" and "File Manger" to find the backup and copy it to the SDCard.
   May even be able to rename it BOOT IMAGE, but not tried that.
5. Shut down

1. I now Booted the faulty S3 in to Recovery
2. Backed up the Phone as above (I did this to create the BACKUP folder for TWRP): "Backup" selected BOOT partition to backup, "Swip to Back up".
3. Then used the "File Manager" to find the BACKUP folder, within which is another folder with a long name (4df159e030809f25 (eg)) within which is "THE FAULTY BACKUP", probably called something like "2015-01-30-08--37-18 omni_19300-userdebug4.4.4 KTU...". Take a note of the name of the file or delete it.
4. Shut Down

1. Insert the SDCard

1. Reboot in to Recovery again
2. Again going in to "Advanced" and "File Manager" find the new backup on the SDCARD and copy it to the location where the faulty backup was/is located. Probably: inside SDCARD - TWRP - BACKUP - 4df159e030809f25 (eg)

1. Then go into "Restore" again
2. Select the good file and restore it - "Swipe to Restore". If the file does not appear it is because it is in the wrong location. there is no browse facility in TWRP Restore, sadly.
3. "Reboot"

All should now reboot in to the OS of your custom ROM.

Hope this helps someone.