[BLU R1 HD Guides, News, & Discussion] vampirefo:
I am not responsible for any damage that might happen to you, your phone, your sdcard your dog and so on, you are responsible for your own actions.

This is a Linux guide, asking about how to on windows will get no replies as I don't use windows.

First thing you need is a micro sdcard class 10, size up to you, in this guide I am using a 32 bit.

You need a micro sdcard reader.

insert the micro sdcard into your reader, insert reader into computer.

Open gparted

find your micro sdcard, delete entire contents format as fat32.

now make two partitions ext4 size up to you.

in this guide I made first one 1GB and other one 6GB

you should now have 3 partitions ALL 3 must be primary

1 fat32

2 ext4

when finished partitioning sdcard, remove from computer place in phone.

reboot into recovery

open micro sdcard on your computer

create a folder on your micro sdcard

call the folder dual_boot copy below file to this folder

https://www.androidfilehost.com/?fid=745425885120701124

your folder should look like this.

Install > dual_boot

Now all you see in this folder is lineage-p6601-Sdcard.zip

look to lower right of twrp you see install image click it.

now you see all the files.

select twrp_sdcard_recovery.img

next you are given 3 choices Boot, Recovery, System image.

choose recovery

swipe to confirm

back

back

back

reboot recovery

now before you continue

mount system

adb shell

busybox df -h

/dev/block/mmcblk1p3 5.8G 12.0M 5.5G 0% /data

/dev/block/mmcblk1p2 975.9M 1.3M 907.4M 0% /system

if you don't see similar to above don't continue

what above shows is data and system both empty and mounted to sdcard.

if you have above you can continue if not repeat steps until you do.

unmount system

install > dual_boot > lineage-p6601-Sdcard.zip

you should see detected filesystem ext4 for /dev/block/mmcblk1p2

let install finish

reboot system

once you see the word android

adb shell

df -h

you should see similar

/dev/block/mmcblk1p2 992M 638M 353M 65% /system

/dev/block/mmcblk1p3 5.7G 43M 5.7G 1% /data

let boot finish

download gapps place on your micro sdcard

once booted, setup, reboot to recovery and install gapps.

reboot system

the above is to setup dual boot, once setup is complete, to switch between OS, boot into recovery

navigate to dual boot

look to lower right of twrp you see install image click it.

choose which boot.img you want to use

next you are given 3 choices Boot, Recovery, System image.

choose boot

swipe to confirm

reboot system

phone_boot.img is the current OS you have on your phone, in my case v17 if you are running something other than v17, use it's boot.img instead, rename to phone_boot.img and replace the one you downloaded from this guide.

to boot to sdcard select sdcard_boot.img

if you just reboot, whatever the current boot.img that you flashed on your phone will be what OS it boots into, the OS is only changed if you flash another boot.img

if you need to backup rom on your phone you would need to flash twrp_phone_recovery.img else you can only backup sdcard OS.

Notice you will see BELOW!!!! on LineageOS

DO NOT TAP TO FIX!!!!!

DO NOT TAP TO FIX!!!!!

DO NOT TAP TO FIX!!!!!

On phone you will see this.

DO NOT TOUCH IT!!!!!

DO NOT TOUCH IT!!!!!

DO NOT TOUCH IT!!!!!

Note first time switching between OS, may take sometime as each OS, is adjusting to new sdcard.

After that should be just like a normal boot.

I have dual booted every device I own for years, never had a problem.

The OS, doesn't care where it's installed works great, no matter if on phone or sdcard.