Multi-booting on Android devices has always been a bit tricky. On regular x86 PCs and Macs, it’s pretty easy to get another operating system boot up. On smartphones, however, the story is different. Fortunately, the brilliant community of aftermarket developers, as well as individual modders, have often come up with different ways to get your Android device to run two ROMs – or even several different operating systems – at once.
When it comes to multi-booting on Android, MultiROM by XDA Recognized Developer Tasssadar is one of the first projects that comes to mind. We also had Safestrap and DualBoot Patcher, of which the first still retains several faithful. Lately, TWRP itself has become another great platform to create a multiboot solution. Now XDA-recognized developer phhusson has thrown his hat in the ring with a demo of a dual-boot solution between his AOSP GSI and One UI ROM on a Samsung Galaxy A71.
Pierre-Hugues Husson, that is to say the person behind the alias “phhusson”, is perhaps best known for his Project Treble GSI, but he has also immersed himself in a number of tools and techniques. different projects that range from incredibly useful to quite fun. The aforementioned multi-start project is one example. It’s called “boot-diverter” and the current implementation requires the end user to press the volume keys to select the operating system they want to boot.
According to the developer, the loader “… sits between boot.img and the system, and can boot unmodified stock and GSIs.” – making it more versatile than Google’s DSU charger. Secondary operating systems can be stored on the SD card, which is also a big plus in terms of portability. At the moment, it cannot change the kernel at boot time, but the solution’s SoC independent structure allows it to run on devices based on Exynos, Qualcomm, and MediaTek chipsets without relying on platform-specific code.
Project on https://t.co/mLXBeme4Py; Tested on Exynos, Qualcomm and Mediatek SoCs. Still not usable for end users, and will probably be considered very unstable forever.
– Husson Pierre-Hugues (@phhusson) April 18, 2021
If Android is all about openness, multi-startup adds a whole new dimension to the idea. For flashaholics, the ability to boot more than one operating system provides the ability to safely try new ROMs or test certain mods without risking the integrity of your daily driver. With that in mind, if you want to check out the phhusson startup derivation project, you can find the GitHub repository for it here. Keep in mind that the out-of-the-box binaries haven’t been released yet, so you’ll need to tweak the code and compile it yourself.