How do I get the device number for TWRP on my Samsung Galaxy J3 2018 model number SM-J337W and root it?

KseniyaK@lemmy.ca to Android@lemmy.world – 18 points –

I have a Samsung Galaxy J3 2018 (model number SM-J337W) on which I want to install my own custom AOSP ROM (because I don't want Google or Samsung to spy on me, I'm stuck with my current phone, and my phone is not supported by LineageOS, GrapheneOS, or CalyxOS). I have managed to install ADB for Linux and unlock the bootloader, but I can't download any TWRP binaries because my phone is not on the list of officially supported devices. I believe i've found the source code for TWRP on this Github page: https://github.com/minimal-manifest-twrp/platform_manifest_twrp_omni. However, I'm not really sure how to build it. According to the code lines bellow, I believe it requires some kind of device number or code:

cd <source-dir>; export ALLOW_MISSING_DEPENDENCIES=true; . build/envsetup.sh; lunch omni_<device>-eng; mka recoveryimage

or if I'm not using a recovery partition:

cd <source-dir>; export ALLOW_MISSING_DEPENDENCIES=true; . build/envsetup.sh; lunch omni_<device>-eng; mka bootimage

Also, I am not sure whether or not if my device uses a recovery partition or not. How do I find that out on my specific device?

Also, when I open up AIDA64, then go to System -> Device, it says j3topltecs. Should I use that for my device number/code?

Also, please keep in mind that this is my very first attempt at rooting any Android smartphone so sorry if I sound like an idiot noob. I also use Linux and don't have Windows installed.

Also, is there any way I could tell lunch (or whatever tool does the compiling) to use only a specific number of threads because if it starts compiling using all 8 threads then my PC will definitely overheat.

PS. Do I even really need TWRP? Has anyone ever managed to install a custom ROM on this specific device?

6

there's often unofficial builds of TWRP and lineage on the device specific XDA forum

You'd probably be better off asking on XDA under your specific device's subforum.

I haven't rooted or installed a ROM on any devices in like 6 years, but it was possible to install a ROM just using fastboot to flash the partitions, it isn't as easy since it takes multiple command strings. It should still be possible since all TWRP does is flash partitions. You'll just need to flash each partition manually or write a shell script to save you the typing.

if the phone has ab system partitioning then it wouldn't have a separate recovery partition. your phone seems to not even have an xda page for it so there isn't really anything made for it. building recoveries and roms is more complicated than it seems. idk how it works for recoveries but I know for building roms you need device trees and stuff. your phone probably doesn't have those already made for it so that means you have to make them yourself somehow. as you can probably tell this is quite above what I know how to do

I've had older lineage running on a J3 , don't think it was exactly the same model. At that time it was as simple as building it with brunch, lunch etc. with the right device name , probably something like j3ltekx , you should be able to find that on the internet. It might be more difficult trying to get a newer version to work on that model since it hasn't been maintained

Well, I just found a guide on how to install twrp 3.2.3 on a Samsung Galaxy Star here, which has the model number SM-J337T. It has the exact same SoC, CPU and GPU as my device. The guide has a link to an unnoficial twrp recovery.img image. Would it be safe for me to use that for my SM-J337W?

PS. What does the T and W mean in the device model number?