The Android operating system’s foundation is the Linux kernel, Yes, that Linux: the one that has it’s own operating system and is commonly used by tech enthusiasts on laptops and desktop PCs.
Every operating system needs to have a kernel as the innermost piece of its foundation. From there the Android and Linux operating systems begin to change quite a lot, but it does always mean that Android, like Linux, is always going to be based on open source software.
Linux being the open source environment that it is has allowed it to develop into a great many distros—roughly as many as 50 of them are available for people to choose, each with their own userbase that prefers it over any of the other 49 options available. The difference in distros has allowed people to pick one that best suits their needs; it isn’t just about what is the best but rather what distro makes the most sense for each person to use based on what they’re looking to get out of it. What it all boils down to can be summed up as customizing the operating system.
Android doesn’t have that: there are no distros to choose from, nothing by way of customizing that you can do to help pick a version of it that best suits what you’re looking to achieve. At least not with the stock software that Android comes with anyway. If you do have the stock software, then all you can do is choose from whatever changes there are to be made from the software that you see, tapping and holding the icons, visiting the Settings application and toggling a few things here and there, and so forth.
But what Android does have up its sleeve, however, is lots of third-party developers out there who are creating custom software based on that same Android foundation but then compiling a bunch of different apps and features that make it unique. And there isn’t much difference between that and what a Linux distro is: distros are the same kernel with different applications and layouts that then make them unique versions.
I’m not for a second suggesting that it wouldn’t be better to have it the way Linux users do: to have official distros that make you feel all warm and fuzzy with the secureness of knowing that it’s all done as official builds. But you also shouldn’t underestimate the knowledge and skills of some of these third-party developers who are responsible for creating the custom ROMs. There isn’t a great deal of financial backing for these custom projects that third-party developers take on in their spare time so the way they get presented can seem a bit of a letdown, though we also shouldn’t forget that some custom ROMs have gone on to become so well-liked that manufacturers have preferred rolling with those ROMs out of the box instead of the official Android builds. Take the OnePlus smartphone for instance that was shipped with CyanogenMod.
Details of Note
- The custom recovery images available in this guide are only to be installed on the Samsung Galaxy J3 2016 Qualcomm (SM-J320YZ) smartphone. Most devices have a custom recovery image developed specifically for it, and you shouldn’t install one that is intended for another device unless advised it is okay by a professional.
- The codename for the Samsung Galaxy J3 2016 Qualcomm (SM-J320YZ) TWRP Recovery image is “j3lte.” You will see that codename in the TWRP image file path and also from your About Device menu so you know you are flashing the right file on the right device.
- You can find the device tree files over at its GitHub page.
- You can install the official TWRP Recovery application from the Google Play Store or from the TWRP website as an apk, if you have root access on the device already, and get the TWRP installed that way, no adb required. Once the app is installed, it will be in your Downloads folder. Navigate to the Downloads folder and select the TWRP application. When the application opens tap on the option for flashing the TWRP.
- Download on your computer the latest version of TWRP Recovery: Primary (Americas) | Primary (Europe).
How to Install TWRP Recovery on Samsung Galaxy J1 Ace (SM-J110)
Note: The Odin flashing tool is really easy to use, but it only works on the Windows operating system. You won’t get the flashing tool to load on a Mac or Linux computer. It doesn’t really matter what version of the Windows operating system that you’re using as long as it is something above Windows XP.
1. Download and install the Samsung USB drivers on the computer if you don’t have them already.
2. Download the firmware (.tar) file from the links above directly to the computer. Extract the file by right-clicking on it and choosing the option to extract. When you do, you’ll see the tar.md5 file inside. That’s the file you’ll be using to do the flashing.
3. Download the Odin flashing tool. It doesn’t really matter what version, but the latest is the most up to date so grab that one. Extract the Odin file and then double-click on the Odin executable file (.exe) that is found from within the Odin folder after extraction. You should now have the Odin interface open on the computer and waiting for you to connect to it.
4. Boot the Samsung mobile device into the Download Mode by first powering it down and then rebooting by holding the Volume Down + Home + Power keys at the same time.
5. A yellow warning triangle will come up on the device’s display. At this time you need to press the Volume Up button. You’ll then see the device getting into the Download Mode. It’s then ready for the flashing.
6. When in Download Mode, connect the Samsung mobile device to the computer with the USB cable.
7. If you have installed the USB drivers correctly, the Odin flashing tool should detect your device. You can tell this by observing the ID: COM port lighting up with a color, usually yellow or blue.
It doesn’t matter what color, it’s the lighting up that counts.
8. After the device is picked up by Odin, click on the PDA or AP button, depending on what button your version of the Odin flashing tool has.
9. Navigate to the stock ROM folder and upload the tar.md5 file to this location in Odin.
10. Without changing any of the default settings, click on the Start button in Odin, and the flashing then begins.
11. Wait until Odin shows a Pass message before disconnecting your device.
You can now close the Odin flashing tool and continue using your computer if you like.
TWRP App Installation Method (Root Required)
If you decided to download the TWRP application from the Google Play Store or the APK file from the official TWRP website, then after you open the application you will be given a few different options to choose from. But before even going that far, it’s important to note that you should only install the TWRP APK file from the official TWRP website. If you’re installing it from Git, or any other file hosting website, it might not be the official version, and thus, it won’t have been built or tested by the official TWRP developers and maintainers.
Once the application is open, you’ll need to agree to not hold anyone from TWRP responsible for any issues that your device may face while using the application. This is a standard disclaimer that Team Win puts on top of each of the recovery image files from the official website as well, so it’s nothing new. It just explains that it is your decision to put the custom recovery on your device, and while they work hard to provide a quality product, there are no guarantees that your device isn’t susceptible to damages relating to TWRP while the custom recovery is installed. You can grant the application root permissions now as well. Root access can be obtained by flashing SuperSU, or other appropriate rooting files, from the custom recovery itself. Without root, you won’t have access to some of the app’s features, such as image flashing. It’s here also where you can enable InsightCore (a feature to monitor and record the network performance of your device).
Once you’ve accepted the agreements, you’ll see the TWRP application’s home screen, where you can choose to flash TWRP or view the network statistics. When choosing to flash the custom recovery, you’ll need to scroll and select your device from the list to make sure you are flashing the correct file. When the device is chosen, the TWRP application automatically then searches for the latest version of the TWRP for that device and will continue doing so every day for as long as the app is installed. This interval can also be altered from the Settings in the top right-hand corner of the device’s display when the apps open.
If root access has been enabled, you’ll see the chance to select the custom recovery image and the buttons for flashing the images to boot or from recovery. You should choose to flash the images to recovery. Only use the boot image flashing when you are flashing full boot images, not just kernel zimages.
DD Installation Method
You can also get the custom recovery installed on the Samsung Galaxy J7 Exynos SM-J700 smartphone by using the DD install method. To do it this way, download the latest recovery image file for your device from its downloads page on the official TWRP website (Primary [Americas]| Primary [Europe]) and then place the file in the root of your /sdcard folder. Rename the image “twrp.img.”
You then need to run the following commands from the ADB shell or a Terminal Emulator application:
dd if=/sdcard/twrp.img of=/dev/block/bootdevice/by-name/recovery
Installing official software updates after having a custom recovery installed is not supported by the custom recovery developers. That’s not to say that it isn’t possible to return to the stock ROM, but it can lead to unexpected behavior if you do. Official updates that come directly from the manufacturer as over-the-air updates are often differential updates, which means they don’t run through the system partition and oftentimes they don’t even completely remove the old files, preferring to use some patchwork over the existing files instead. All that is fine and can help you save data, but if you start installing these differential updates again after you’ve previously had a custom recovery installed, that’s when some unexpected behavior can occur.
It’s also possible for a manufacturer to make changes to the recovery images, and when you reinstall them, the changes could potentially conflict with the custom recovery that was installed. There is no way for the custom recovery developers to get their hands on the source code of the stock recoveries which is why nothing can be done about it.
When you install an official Samsung stock ROM, you are removing the root access and the custom recovery image that you may have had. Instead of doing that it is advised that you wait for a new custom ROM that is based on the same Android version to arrive, which usually happens only a few days later than the stock software rolling out.
There isn’t technically a way for you to uninstall or remove TWRP Recovery. Your device always needs to have a recovery partition installed at all times. So what you can do is replace the custom recovery with a stock recovery again. Assuming you’ve already read the warnings above, you can do that a couple of ways, both of which involve the stock ROM zip files. You can either unpack the firmware zip file and then flash the recovery image that is found inside, usually done the same way that you flashed the custom recovery. Or flash the complete stock ROM and it’ll replace the stock recovery at the same time. The way you flash the stock ROM will depend on the manufacturer. For Samsung devices, there is the Odin flashing tool that you can install on Windows operating systems.
If you get a message stating that you have on OS installed, it likely means that you managed somehow managed to wipe the system partition. Given the sensitiveness of how the system partition can change the way your device operates, this is not the ideal scenario to find yourself in, but there are ways out there for you to fix it.
If you have already taken a backup, then you should be able to restore that backup from the custom recovery menu. In such cases, the backup will then reinstall the system partition and leave you with a working operating system. If that doesn’t work though, or you didn’t take a backup yet, you can try getting back to stock firmware for your device instead. For Samsung devices that is by using the Odin flashing tool and then flashing the stock ROM using Odin on a computer.
- How to Install TWRP Recovery on Samsung Galaxy J2 (SM-J200)
- How to Install TWRP Recovery on Samsung Galaxy J1 Ace (SM-J110)
- How to Install TWRP Recovery on Samsung Galaxy Express 2
- How to Install TWRP Recovery on Samsung Galaxy Grand Prime VE