Well it has been a long time coming but we finally have a working Jelly Bean 4.1.2 ROM that can be flashed onto the ICS phones!
It started with Shinru2004 and his nandroid dump of a Sprint 4.1.2 Force 4g. SuperR took that nandroid and made a flashable debloated, rooted, de-odexed zip. Unfortunately neither of these would boot on a device which previously had ice cream sandwich installed.
I was able to get it to boot by modifying that ROM by replacing the updater-script, updater-binary, and zImage with ones from DSF .7. That was with the 3.0.8 kernel and some things did not work (wifi, bluetooth, camera). To be expected when using system image from 3.4 kernel with 3.0.8 kernel, but calling, text and data did work.
Shortly after, Downgraded286 posted that he had a textnow phone with 4.1.2. I asked him to use online nandroid backup to get a nandroid because I knew that this would include the modem.img and thought that might be the underlying issue.
I flashed that modem.img and the result was I couldn't get any ROM to boot except my modded JB rom with the old kernel and then there was no network connectivity at all and some other issues.
So I downloaded the ZTE Boost ROM that is up on ZTE's website and took a deep look at the updater-script and the image files that were included. There were many more than what you would normally see inside a custom rom, so I again asked Downgraded286 if he would be willing to use dd to copy all of the partitions that corresponded to the image files in that ZTE ROM, and here SuperR stepped up again with a script which would do just that.
Downgraded286 ran that script and uploaded the results and just now, tonight, I renamed those image files to match the files from the ZTE ROM, copied them into the SuperR debloat/deodex, made the corrseponding additions to the updater-script, zipaligned, signed, and built with rom kitchen...and BAM! It works!
I had just restored my phone to ICS with the ZTE rom so I had to reinstall CWM (which meant rooting, which cannot be done with 1 click root anymore on that rom, but towelroot worked, the newer zte boost rom also has swype included, but not the JB rom. Really different from the first boost rom I had). Anyway I got cwm installed, wipe factory reset, wiped dalvik, installed the zip and it booted! Everything works! Camera! Bluetooth! WIFI! Data! Everything!
Finally ZTE Force 4g users who had ICS can upgrade to JB! It's only 2 years late, but here it is!
This ROM should work with Sprint, Virgin Mobile, and Boost! I will be adding another link here later for TextNow users with ICS who want JB.
Keep in mind this is a very bare, basic ROM (being debloated) but it is small and I would say will make an excellent base ROM for future dev. I believe it's noticeably faster than ICS but haven't benchmarked anything yet. Very responsive.
If you flash this and decide that you want to go back to an ICS rom you will have to install the ZTE boost rom from the zte site at this link FIRST
http://www.zteusa.com/media/wysiwyg/boost-force/update.zip
Just making a nandroid and flashing back to it will not work.
That is because this JB update will update your aboot, modem, tz, and other firmware partitions to the version required for Jelly Bean and a nandroid will not backup these partitions. If you flash an ICS rom right after this without using the zte boost rom to first restore those partitions it will not boot. You have been forewarned. Also you need to use the original recovery which is stickied in the forum to flash the ZTE update.zip (unless you care to modify the updater-script first). If you have CWM you can use that to reboot to bootloader, or adb, and then use fastboot to boot the original recovery image. After you reflash the ZTE boost ROM if you want to reinstall CWM and go back to your nandroid, install CM or DSF, whatever, reroot with towelroot then follow the instructions for installing CWM recovery.
These instructions apply to downgrading from JB to ICS only, to install JB just download from the link below, reboot into CWM, wipe data/factory reset, wipe dalvik, and then choose install zip from external sd card and select the file from the link below.
Here is the public link to the Jelly Bean ROM in my dropbox.
https://www.dropbox.com/s/5zg761yz3p5yda2/ZTE_FORCE_JB_SAWBONES.zip?dl=0
And on Mega
https://mega.co.nz/#!WwUAWRwC!c7UKnKvHzurIdrE6hLOx5kbAi5y7b1KKtVKw5vKXesk
Here is the MD5 sum for comparison: bc1c0576e3ac925613eb9ec476e6197e
A VERY SPECIAL THANKS GOES TO THOSE WHO HELPED IN THIS COMMUNITY EFFORT!! SHINRU2004 FOR THE ORIGINAL NANDROID, SuperR FOR BUILDING THE ORIGINAL FLASHABLE ZIP AND THE SCRIPT WHICH DUMPED THE PARTITIONS WE NEEDED, AND A HUGE THANKS TO DOWNGRADED286 FOR BEING WILLING TO HELP US GET THE MISSING PIECES WE NEEDED TO MAKE THIS HAPPEN!!
PROPS TO TEXTNOW SUPPORT ALSO FOR BEING WILLING TO SHARE THE ROM OPENLY, EVEN THOUGH IT DIDN'T HAVE THE PARTITIONS WE NEEDED TO UPGRADE FROM ICS TO JB.
I did choose to use the sprint source bc it has config for sprint, boost, and virgin mobile included. Why Boost and Virgin Mobile have not released this, and Sprint never made it an OTA update, I have no clue! The textnow rom is very much branded textnow and oriented toward their SIP service and so I will release a textnow update separately in another post in this thread.
Cheers all and enjoy! Look for me to soon release a ROM with some more features added in (like the swype from the ZTE rom) and some other goodies.
-SB
Oh I almost forgot, shout out to those who were willing to test the earlier versions of this work such as TheFatDemon and Knoober! Tester feedback is important and I hope people will try this. It's really a step up in performace.
