[Galaxy S 4 Developer Discussion [Developers-Only]] RavenII:
Background: Work bought me an S4, but they use Verizon...I use T-Mobile. I must solve this issue. (Plus it's been so long that since I've even opened my QXDM/QPST that I almost...almost forgot how to use it, man, I miss it)...

This is more of a running log to potentially help others in their endeavors. This is an advanced topic...by today's standards. There is a LOT you need to know before just jumping in on this...unless you're like me and don't mind bricking a device for the sake of learning...then, carry on.

BTW, As you can clearly tell..I don't do super formatted frilly assed colorful posts...

ONWARD!!

What is known so far:

1. The modem MDM9615m is capable of anything...(Maybe even making you tea).

2. Using either 2009031920090615 or 2010031619780721 as the 16 digit PW in QXDM allows you to use "Software Backup" to backup and restore QCN files...(Both work, only one puts the phone offline)

4. The AWS band method that is floating around here (337_aws.qcn) doesn't work...it actually breaks the phone. (more on that later)

5. Putting your backup on again leaves whichever fields the 337 file had intact...so say you put the 337_aws.qcn file onto the phone, it stops working...however, you restore your backup...and the phone starts working again but all the fields of the NV that were written by the 337 file remain. Though phone functionality is restored.

6. MDK or ME7...doesn't matter at this point...no effect on functionality.

7. Flashing an MD1 modem/NV Backup from a T-Mobile Note II (which also has the 9615 doesn't seem to work...yet)...It actually kills the phone...I'll update when/IF I revive it...

8. You can Odin your modem back...whew!

What needs to be explored:

1. Whether or not flashing (shoehorning) another carriers radio will help (or if it's even an option)...this would probably have to be a regional carrier or maybe an international (non US) carrier's radio. Usually the bigger carriers can tell the manufacturer what to leave out/put into their phone...

2. Which NV Items need to be modified in order to get AWS (maybe even LTE) working.

3. Can a backup of another phone....let's sayyyy a T-Mo S4...be made and dumped onto the i545.

4. What complications are there? Is this permanent, can the phone be put back to "normal"? etc. etc.

5. If, as a last resort, we can edit the current parameters that are in the NV of a stock i545 to simply "reroute" (work with me here)...what bands it uses for which function...(this is the most tedious...but most undoable method...that I can think of....so far).

Troubles I've already ran into:

As mentioned before...after you write the 337_aws.qcn file to the phone it's pretty much set in stone...for now. When this happens, the modem starts boot looping...I'm sure this is due to bad parameters since the 337_aws.qcn file was probably from a 9215, i545 uses a 9615...you will not be able to access it again in QPST/XDM...

You'll have to get into Settings, More Networks, Mobile Networks, Network Mode, and select GSM/UMTS...this will keep the modem alive for you to be able to play with it again.

So far that's it. I've only been able to start messing with this phone in the past day or so...so, I'm sure this thread will be my dumping ground for my progress/findings/ideas...etc. Again, I encourage anyone that wants to help....to do so. I'm always open for collaboration. :)