Unofficial TWRP enables true dual boot on the OnePlus 7 and OnePlus 7 Pro
OnePlus phones are often touted as the spiritual successors to the Google Nexus lineup due to their hackability. The debutant OnePlus One can run Android 10 or even Ubuntu Touch without any issue. Advanced mods, such as multi-booting, is quite a well-known hack among the community. Now XDA Recognized Developer Zackptg5 has expanded the concept of multi-booting on OnePlus phones to a whole new level by rebasing the idea on the A/B Partition Scheme and released a brand-new dual boot solution for the OnePlus 7 and 7 Pro (including the 5G variant).
Back in 2016, XDA Senior Recognized Developer Dees_Troy i.e. the lead developer on the Team Win Recovery Project, hinted about the idea of utilizing the second set of partitions in the Google Pixel series to dual-boot. Zackptg5’s method basically does the same, as it offers a custom version of TWRP that allows splitting the userdata partition into two separate slots for true dual-booting. For enthusiast users, another layout featuring A/B/C userdata is also available, where ‘C’ is a common data partition shared by both ROMs.
According to the developer, the custom build of TWRP is based on the regular TWRP for the OnePlus 7 lineup maintained by XDA Senior Member mauronofrio, which is itself a mandatory prerequisite for installing the mod. XDA Senior Member cosmicdan is also credited, as Zackptg5 might be inspired by his works on Project Treble bringup for the Xiaomi Mi A1. Last but not least, we can also find XDA Recognized Developer topjohnwu‘s name in the credit list, as the almighty Magisk is absolutely needed to create the A/B/C userdata layout.
The source code of this mod is hosted on GitHub. Zackptg5 has also posted common troubleshooting methods as well a guide to revert back to the stock partition layout in the XDA discussion thread. While repartitioning is always a risky job, one can use the device-specific unbrick tool (OnePlus 7, OnePlus 7 Pro) if things go south. Keep in mind that any repartitioning will wipe all of your data.