Samsung Galaxy S9 and Galaxy S9+ can now boot official TWRP
Shortly after the launch of the Samsung Galaxy S9 and Galaxy S9+, we saw the kernel source for both devices get officially released. This kicked off the development community here on the XDA forums to get working on these devices right away. Only a couple of weeks later, Team Win Recovery Project (TWRP) has been released officially for both devices by XDA Recognised Developer and Contributor jesec, a crucial element in getting custom ROM development off the ground.
A custom recovery such as TWRP is necessary for a whole number of reasons when it comes to ROM development. Its primary purpose is exactly what it says in the name: to recover your device should any custom software flashing go awry. Without a custom recovery, it’s often straight up impossible to even flash a custom ROM as the OEM’s recovery will usually restrict non-official software from being installed. The only restriction currently is that TWRP is unavailable on Snapdragon editions of the device, thus leaving a huge amount of American users in the dark. This is because Snapdragon editions of Samsung devices tend to be carrier-locked, and the bootloader can’t be unlocked as easily as the international Exynos variants which come straight from Samsung.
What’s more, as the Samsung Galaxy S9 and the Galaxy S9+ both launch with Android Oreo, Project Treble is in tow for both devices. With the availability of official TWRP, you can flash a custom ROM on your Galaxy S9 or S9+ right now if you want. Be sure to use TWRP to back up your system partition first. Simply by flashing the system.img file through fastboot or through TWRP, you can boot stock Android on any Project Treble enabled device. It’s the first Samsung device to support it, and even more so, the first Exynos device as well. It’s likely there will be some initial bugs, but it should boot and work fine for the most part. Be sure to give it a try if you’re interested, and hopefully custom ROMs start to arrive for both devices soon!