[Nexus 6P General] t83wood:
Haven't seen anyone else discussing this particular solution yet so figured I'd share that we can boot multiple roms using dual boot patcher by [MENTION=4277844]chenxiaolong[/MENTION].

*The only things I'd recommend are the following:

*MAKING A BACKUP FIRST IN RECOVERY. Especially if you've never used the app, this helps in case you misunderstood something or didn't read enough or didn't think enough or the dog ate your homework. :P

*I recommend using TWRP version 3.0.3-0 which can be found here - https://dl.twrp.me/angler/

* I have not tried this with f2fs only ext4 so naturally I'd only recommend using ext4 partitioning on your device.

* If your device is encrypted in any way booting multiple roms will not work, which should be obvious but I'll state that anyways. Thanks [MENTION=5171112]JKforUA[/MENTION] for helping us figure this out.

*If you want to boot more than just two roms, that you use the data slot options for your roms which can be named anything you'd like and they will be stored on the phones internal storage.

* Make sure you're on the latest Radio and Bootloader for the nexus 6p, I flashed this and it works fine and is backwards compatible with Marshmallow roms.

Radio & Bootloader link -

https://xdaforums.com/nexus-6p/general/nexus-6p-radio-bootloader-recovery-t3433637

* Use the patcher app to update the ramdisk and set your primary rom's kernel as Primary before patching or flashing anything.

*If you use the fingerprint scanner you'll have to delete the file /data/system/locksettings.db in each multi boot directory, this disables getting an incorrect pin error when switching roms.

*If using a marshmallow and nougat rom you'll need to flash the appropriate vendor image in recovery before boot.

*Vendor images should not be patched.

This process is fairly simple to me because I've been using it for years but if you have any questions feel free to ask in this thread and hit thanks if I helped ya.

* Before reporting errors I would suggest you try the following steps-

1. Make sure you're using this version of the patcher app because it is the one I have been using without issue -

Version 9.1.0r80-

https://dbp.noobdev.io/files/9.1.0....atcherAndroid-9.1.0.r80.gd5920b2-snapshot.apk

2. Make sure you have enough free space to have two of the zips you want to use because that is what you will have after you patch.

3. Make sure your path to the zip is correct when browsing for the zip, go through internal storage to the directory where the zip is.

4. If you get any error patching, uninstall the patcher app, re-download it, and reinstall it.

5. There is also a Windows version you can try if you prefer.

*If you are still having issues we can discuss it here, and if nobody can seem to come up with a fix in this thread then errors can further be reported by following instructions here - https://dbp.noobdev.io/downloads/

Credits - [MENTION=4277844]chenxiaolong[/MENTION] for the patcher app!

Links :

Dual boot patcher (All versions) - https://dbp.noobdev.io

Original forum - https://xdaforums.com/showthread.php?t=2447534

* Screen shots of my current setup attached below for additional guidance if desired.

Status - sharing, using, in some cases testing, always learning (^_-)...