Boot multiple roms on nexus 6p using Dual boot patcher! - Nexus 6P General

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 @chenxiaolong.
*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.
*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 @JKforUA 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://forum.xda-developers.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 - @chenxiaolong for the patcher app!
Links :
Dual boot patcher (All versions) - https://dbp.noobdev.io
Original forum - https://forum.xda-developers.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 (^_-)...

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Thanks for sharing, I've never heard of this before. A few questions;
How similar/dissimilar to multirom is this?
Do I need a specific kernel, or will it with with any kernel?
I briefly read through the original thread, am I creating a zip that flashes two Roms, or is the zip something that flashes alongside the ROM I currently have?

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Thanks for sharing. Used this on my further G4. Didn't know that our device is supported. So no need to wait until multirom is working on 7.1.1. Gonna play around now.

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Where do we report errors? I was about to patch several files and the app crashed. I have a couple log files.

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DaringDomino3s said:
Thanks for sharing, I've never heard of this before. A few questions;
How similar/dissimilar to multirom is this?
Do I need a specific kernel, or will it with with any kernel?
I briefly read through the original thread, am I creating a zip that flashes two Roms, or is the zip something that flashes alongside the ROM I currently have?
Click to expand...
Click to collapse
I actually prefer it because it's what I'm used to, you can patch whatever kernel you choose and flash it in recovery, reboot into that rom, open the patcher app, set kernel, profit.
Basically you patch the rom zip you want to flash as secondary, or in my case data slot, naming them 2 and 3 because the Multislot options won't flash anything for me but using data slots works fine. Patch rom, patch gapps, patch whatever kernel, flash all in the whatever succession recommended by the rom op, and you'll automatically boot into the newly flashed rom when you reboot.

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OmegaBlaze said:
Where do we report errors? I was about to patch several files and the app crashed. I have a couple log files.
Click to expand...
Click to collapse
Hmmm I found this
https://forum.xda-developers.com/showpost.php?p=64727670&postcount=8259
I would try re-downloading the app because I haven't had it crash in any roms I've used yet, I just grabbed the latest build, installed, opened, granted root when prompted, updated the ramdisk if needed which is indicated the app, rebooted when prompted, set kernel, and done.
If it's still crashing for you there's the usual force closing the app from your roms settings and clearing the apps cache and data but you probably already tried that?

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t83wood said:
I actually prefer it because it's what I'm used to, you can patch whatever kernel you choose and flash it in recovery, reboot into that rom, open the patcher app, set kernel, profit.
Basically you patch the rom zip you want to flash as secondary, or in my case data slot, naming them 2 and 3 because the Multislot options won't flash anything for me but using data slots works fine. Patch rom, patch gapps, patch whatever kernel, flash all in the whatever succession recommended by the rom op, and you'll automatically boot into the newly flashed rom when you reboot.
Click to expand...
Click to collapse
I'm gonna play with this over the weekend, I like new stuff!
So whatever fkashable zip I patch will be designated during the flash as secondary (or whatever) and won't overwrite my current ROM allowing it to exist along side it?

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DaringDomino3s said:
I'm gonna play with this over the weekend, I like new stuff!
So whatever fkashable zip I patch will be designated during the flash as secondary (or whatever) and won't overwrite my current ROM allowing it to exist along side it?
Click to expand...
Click to collapse
Correct, so long as you don't patch it as Primary. It will tell you where it's flashing to in recovery. You can also use the dual boot patcher recovery zip for things like switching roms from recovery and wiping roms, wiping multiboot files will get rid of a rom in its entirety if you wanted to replace it with something else. I've always installed the patcher app in my other roms after first boot and used it to set the kernel for that rom too.

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t83wood said:
Correct, so long as you don't patch it as Primary. It will tell you where it's flashing to in recovery. You can also use the dual boot patcher recovery zip for things like switching roms from recovery and wiping roms, wiping multiboot files will get rid of a rom in its entirety if you wanted to replace it with something else. I've always installed the patcher app in my other roms after first boot and used it to set the kernel for that rom too.
Click to expand...
Click to collapse
If I'm patching for the data partition, am I correct in making all zips (ROM, Gapps, and su) to the same name? (Ex. I named the ROM zip slot "rom2", and then used the same name for the other zips)

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DaringDomino3s said:
If I'm patching for the data partition, am I correct in making all zips (ROM, Gapps, and su) to the same name? (Ex. I named the ROM zip slot "rom2", and then used the same name for the other zips)
Click to expand...
Click to collapse
Yep looks good!

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t83wood said:
Yep looks good!
Click to expand...
Click to collapse
Awesome, thanks, I'll see what happens :good:
Edit: it worked! It's a little more involved than multirom, but it seems to be fine! Easier than I thought.
I've not yet switched between the two, but the app on the secondary (data slot) recognizes the primary

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Wow great. Running great on data-slot. Even magisk is supported. Good to have a new playground. Happy to have the 128 GB variant. Gonna do some test with Viper.

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How do I switch roms

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All perfect. Viper running with magisk. Every rom i tried booting without any problem. So atm the perfect tool to test other rom!
---------- Post added at 11:45 AM ---------- Previous post was at 11:43 AM ----------
DEVILOPS 007 said:
How do I switch roms
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Click to collapse
Install dualpatcher app and choose rom in 'ROMs'. Then reboot. Or run utulities in twrp (install).

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What do I do? It says failed error code - 1 tried doing cortex rom and selecting data. Is there something I need to do?

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DEVILOPS 007 said:
What do I do? It says failed error code - 1 tried doing cortex rom and selecting data. Is there something I need to do?
Click to expand...
Click to collapse
Cortex also flashes the vendor. Maybe this gives the error because in dualboot all roms use the same vendor partition (could be a problem to flash vendor through dualpatcher...). All other roms i tried vendor was not included to flash (only rom und gapps separately). I am just trying cortex too (just ready to flash). Gonna report, if i succeed.

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Donric13 said:
Cortex also flashes the vendor. Maybe this gives the error because in dualboot all roms use the same vendor partition (could be a problem to flash vendor through dualpatcher...). All other roms i tried vendor was not included to flash (only rom und gapps separately). I am just trying cortex too (just ready to flash). Gonna report, if i succeed.
Click to expand...
Click to collapse
Okay thanks Bro, I might try out lineage. Also open gaps failed for me bit do I need the rom first or do I need to use dynamic gaps? I appreciate the help!

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DEVILOPS 007 said:
What do I do? It says failed error code - 1 tried doing cortex rom and selecting data. Is there something I need to do?
Click to expand...
Click to collapse
Cortex rom running fine on multiboot on my device. So no problem with vendor in multiboot. I can also switch back to another rom. As gapps i suggest you to use only dynamic gapps (banks gapps). I always use mini dynamic gapps. Opengapps give many problems.... On primary i got rr oms-release from 12.01. ATM running with 3 different rom all on internal sd card. Just pay attention to give always the same name when patching a zip file in dualpatcher.

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Donric13 said:
Cortex rom running fine on multiboot on my device. So no problem with vendor in multiboot. I can also switch back to another rom. As gapps i suggest you to use only dynamic gapps (banks gapps). I always use mini dynamic gapps. Opengapps give many problems.... On primary i got rr oms-release from 12.01. ATM running with 3 different rom all on internal sd card. Just pay attention to give always the same name when patching a zip file in dualpatcher.
Click to expand...
Click to collapse
What do you mean by same name? I am on pimps rr oms and whenever I flash any rom it says error code - 1. Any idea what I can do?

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DEVILOPS 007 said:
What do you mean by same name? I am on pimps rr oms and whenever I flash any rom it says error code - 1. Any idea what I can do?
Click to expand...
Click to collapse
Did you flash in twrp (3.0.3.0)? I only use twrp to flash a new multiboot rom. Before flashing a new rom just make sure, you patch all necessary zip files (rom, gapps, etc.). Same name means u choose where (on angler i always choose Data slot - this is internal sd card). Then you give the name (no capital letters) and choose the directory to save the patched file. This you do with every zip file for the rom u gonna flash. The new zip file have the original name and the text "....._data-slot-namegiven.zip" (example for data-slot). The part "data-slot-namegiven" should appeir in every name of the patched zip file. I think with our device it's goot to use the data-slot if you have enough space on your internal sd-card. Using Multi Slot could lead to space problems on system partition of the device. Then just flash the patched files one after another in twrp. Don't forget to flash also patched supersu.zip oder magisk.zip to get root (if it's not in the rom included). You need to patch gapps and supersu or magisk for each slot separately. The name of the patched file just says the path for the multiboot rom. So twrp flashes the patched zip to the right place. Sorry if i wrote to much. Hope it's gonna give you some help. More information you find in the original thread of multiboot.