Uscc 6800 Gps, Custom Roms, Downgrading Guide

[ImCoKeMaN]

Um, Trust me its WAY more risky than just normal OS flashing. There is part of the radio that will never be overwritten after going to GPS radios (by current known means) despite the version number actually changing. This can lead to bricks (see sig) but not always immediately. Additionally, there could be some random incompatibilites with an inconsistent radio image.

[tiermann]

Any link other than http://ppckitchen.org/downloads/buildos.msi does not guarantee the latest stable release.

[maverick351ci]

Colonel, Thank you, and i plan on putting a nice big red warning on the top of it when i get around to post it up here, i do agree that people should be warned, even though anything you find for information is use at your own risk on the net

[maverick351ci]

ImCokeMan - True, the downgrade is more for getting settings back so you can reupgrade to the GPS rom, or if you was getting rid of your phone, warrenty whatever you may want to, or for the daring like me that will give it a try, if it causes problem you can allways upgrade again!

Tiermann - Thanks i changed the link on the first post, but i kinda figured that the updater would get the most current release.... am i wrong?

[puff]

Originally Posted by ImCoKeMaN

Ok, the radio thing seems to really have people confused and understandably so. I was VERY direct with my warnings for a reason. I am certain that your phone does have some code on it that is from the GPS rom, and that may or may not show itself in roms you use that aren't designed for GPS. The radio section is made up of different parts and the one that shows the radio version number is getting flashed, but the part that loads it isn't going to "revert" to stock as it is write protected (something to do with the 785 nbh header). This can cause issues and it was related to what ended up bricking my device.

Sounds like there's a section of the "radio" that doesnt get updated when the radio is flashed back, perhaps i can best explain with this reference... found an interesting fix for Invalid Vendor ID and Invalid Model ID that actually broke WiFi on the Excalibur -> http://forum.xda-developers.com/showthread.php?t=328690 but the solution -> http://forum.xda-developers.com/show...3&postcount=16 involves a dump and some hex editing to correct those problem sections in NaND memory that could not be overwrote. i could be wrong, but i think that's what ImCoKeMaN is trying to point out. That it IS POSSIBLE to downgrade, however the actual NaND memory section that is "protected" may not get overwrote, may become corrupt, could be wrote to different/mismatching memory addresses, and could cause problems... or you could NEVER notice a problem at all...

Originally Posted by ImCoKeMaN

Of course, if you're crazy like me feel free to make bricks. I could use a new patio.

although i would love to learn more about the whole r0m dump, disecting a r0m, and do some good ol' hex editing.... i never find the time, and believe me.. i've been searching. so if anyone wants to h00k me up

[gguruusa]

Originally Posted by maverick351ci

BTW try clicking the link to buldOS i posted, it does work

I know it works right now. Purely coincidental. That was the location of the original release before the downloads folder was set up. Try it now - I bet it doesn't work any more

as for risky, i wouldnt say that it is any more risky than upgrading custom firmware

there's some truth to that. At least when you upgraded, you got GPS hopefully

as with everything, its use at your own risk right?

but maybe, just maybe, if you have a working guide that if you follow it reverting back works, then maybe it will cut down on the people who think they "Bricked" there phone and, or help people who get stuck in a bootloader screen

The reasons for downgrading that you cited aren't worth the risk of potentially bricking your phone. In the case of a possible stock GPS for your carrier, your better off waiting for that to be a reality than theorizing about how to handle it now.

[puff]

you can read more about the downgrading debate here

One Final comment for tonight:

On the Original (not slim) Sony PSP, once you downgrade from an "official" 3.XX release of the firmware back to the kickass 1.5 - you cannot upgrade to any 3.XX "official" version without very high chance of bricking your device. This is due to xtra files left behind in the NAND memory - Although you can install custom firmware so that you have the best features of both 1.5 and 3.XX

Once again, same concept i believe

[maverick351ci]

I understand all of everyone’s concerns, I really do. but here is my deal, during the course of messing with things to get everything back up to normal, I had to downgrade my boot loader to 1.00 then up to 1.20 then up to 2.40 several times as well as go back in radio ROMs and OS ROMs in the same manner to get the sprint customizations off my phone and the ##000000 working again like it did originally when the sprint customizations ran it changed it to ##778 one, now this isn’t a big deal to most but if I was to take my phone in to get it worked on, I didn’t want to have to explain why the epst access was different to the noob working the counter trying to gain epst access to my phone. Most of the people can only follow what there procedure is and not think outside the box. this is just one example of what the customizations change, and im sure that there is another way of fixing them, but everything I read said to go back to the stock ROM for the Alltel users and to do so you must downgrade.......
Correct me if im wrong, but I really do not want to beat a dead horse with the downgrade debate, this isn’t the intentions I had for this tread I just wanted to get some options out there to the USCC users of this device since it is very new in the USCC market and all, finding information on this carrier is very hard to sift trough, and most of what I have listed has come from many different threads on here XDA and random forums found trough Google, I just wanted to compile what does work for USCC in one place you know.....

so if its all the same to everyone, I would like to end the downgrade debate as of this post and save this tread for questions and responses to the process as well as ideas and updating the main topic.

[ImCoKeMaN]

Whatever customizations you collected when you did the downgrade should be saved seperately and made available to everyone so that not everyone does the downgrade.

[mykleh35]

Great write up maverick351ci! thanks for taking the time to write it down and of course for the 'big ones" to get where few of us USCC people have gone! On a related subject we are often asked to THANK SOMEONE when they help you... how do you actually do it??? because you get a big THANK YOU from me!!=D>