[7 Mozart General] paulosaints:
I see some people with problems and doubts when its time to install a custom rom. I was one of them, so now that i've installed a custom rom, its time to share the procedure i've taken!

I am trying to build a tutorial for my case, maybe it can be usefull for others!!

All the info was taken from other topics and posts from XDA

Stuff you must know (from DFT thread):

SPL is Secondary Program Loader. It allows to flash ROMs to device.

Without working SPL device is fully bricked, you can’t restore it. It’s why all operations with SPL are dangerous.

OSPL is Original SPL. This SPL comes with stock ROM and doesn’t allow to flash custom stuffs.

RSPL is Reloaded SPL. It load only to RAM, so it doesn’t persistent. It’s enough to soft reset device to get OSPL back.

HSPL is Hard SPL. It’s permanently flashed to internal device memory and replaces OSPL. After soft reset you still have HSPL instead of OSPL.

For regular users, who flash ROMs rather rare, it can be enough to use only RSPL.

For advanced users and ROM makers, it can be useful to install HSPL.

IMPORTANT NOTES

1. Before doing any operations be sure you have battery level more than 50%!

Sometimes in SPL mode WP7F devices DO NOT charge. You may got a cold brick if it power down during SPL or RADIO update!

2. Stock RUU ROMs have two NBH inside, SPL_Signed and RUU_Signed.

So it's not possible directly flash stock ROM, you need extract files and remove SPL_Signed.nbh at least.

3. Rememeber if you have HSPL and you flashing stock RUU_Signed.nbh you lost HSPL!

4. Supported OS: Windows XP, Windows Vista, Windows 7.

Warranty Issues

Be warned, using RSPL may void your warranty.

If you need to send your device to a Repair Centre, make sure that it looks like stock! Install stock official ROM before go to Repair Centre.

My case is:

Htc Mozart T8698

Windows phone 7.5

Os version: 7.10.8773.98

Firmware 2250.21.51201.401

Firmware 0004

Radio 5.71.09.02a_22.51.50.21U

Radio A.102.0.D4

Boot loader 5.12.2250.1(134578)

SOC 2.2.5.0

What i want to do? FULL UNLOCK IT!

So what i have done...

First of all you must know your Mozart!!

The important numbers, in my case, where:

Os version: 7.10.8773.98 because you must downgrade from 8773 (my case) to 7004

Firmware 2250.21.51201.401 THIS TUTORIAL IS FOR THE ONES THAT END IN 401 ( its called the CHARACTERISTIC VALUE and its CV401)

YOU SHOULD READ more info in this thread from ansar: http://xdaforums.com/showthread.php?t=999405

Boot loader 5.12.2250.1(134578) BECAUSE YOU WANT YOUR BOOTLOADER TO BE IN VERSION 1.28.2250.4

Now you know your numbers I MUST SAY! If your Mozart ends in 401 (CV 401) you can continue, if not this tutorial is not for you!! Sorry, but keep looking!

FIRST STEP!

You shall want to downgrade your rom to 7004 which will also downgrade your SPL to 1.28!! SPL IS THE SAME HAS THE BOOTLOADER!!

You can do it by 2 ways!! Using the cable method (will not do it) or via the asnar method ( THATS IT!! TANX ASNAR)!!

So lets do it with the asnar method which is on this thread:

http://xdaforums.com/showthread.php?t=1413694

READ IT ALL A FEW TIMES!!!

i will not tell how to do it because the asnar thread is obvious, and i advise you to read it a few times!!

I WILL THIS: if during the downgrade process you got the ERROR 270 its because the SPL is version 1.28.2250.3 dont worry it happens to me, i know you are stuck now and the mobile doesnt do nothing instead of showing the bootloader screen!! What you will do now is upgrade the SPL to 1.28.2250.4 ok??

dont worry! just install this one on this thread: http://xdaforums.com/showthread.php?t=858599

So after that you on the correct 1.28, lets keep going...

SECOND STEP

You must want RSPL and then HSPL

so just read this a few times, but its all on the first page:

http://xdaforums.com/showthread.php?t=1195647

If all its ok, now you can add any custom ROM like NextGen, Dynamics, DeepShinninh of NewTech from asnar!!