immun0 - i just successfully debranded a W760a *and* have it updated to the latest firmware with SEUS. In addition, I have also successfully rebranded it to what it was before.
I'm newbie, and I have found (mis)information and (mis)instructions scattered all over the place, making *quality* debrand/rebrand very challenging.
For debranding, picking the right combination of MAIN and FS and custom file is critical, otherwise you won't be able to update it with SEUS when future new firmware comes out before made available on a site like this, *if* at all. SE seems to be pretty good at updating firmwares (unlike Samsung which I have ditched).
For rebranding, above procedure with SEUS does NOT work at all. My W760a's original CDA is 1212-6828, Rev. R3CC005. I had to download those particular MAIN/FS pair and ATT's custom file for rebrand.
In summary, for debrand, I used a2uploader to change to a generic ("customized") CDA, then SEUS to update the firmware.
For rebrand, I flashed everything with a2uploader.
I have a ton of details but I'm too tired to type everything up right now. Ask and I'll reply. Cheers.