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[ROOT][GUIDE] Upgrade Lg Cv1 (X210) to oreo keep working fastboot[GUIDE]

93 posts
Thanks Meter: 7
By Duhjoker, Member on 8th February 2020, 05:01 AM
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Hi guys

I just successfully flashed my K8+(2018) to oreo from nougat and kept my working fastboot. Im gonna tell you how but first........

I Duhjoker am in no way responsible for anything that may befall your device by trying any technique or by following this guide. Do this at your own risk.

What you will need::::::::

Lg K8+(2018) LM-X210ULM

K8+Oreo-rooted-boot.img =====second post

K8+Oreo-twrp-recovery.img====second post

LGUP dual mode

Lg firmware extractor ??? This is for those portting a recovery and boot.img for a different cv1 device

Oreo firmware for your K8+(2018) X210ULM


Nougat firmware for your K8+(2018) X210ULM

Magisk manager


Ok so go to settings and tap general then about phone then software and tap the build number 7 times and to make yourself a developer. Exit about phone and open your newly opened developers settings turn off auto updates and enable oem unlocking and debugging.

Now this guide assumes your cv1 device is on nougat. If you are already on oreo and have no ARB number and want to upgrade your oreo rom to include a working fastboot mode then you will need to first downgrade your cv1 device to the earliest version of nougat firmware you can find and repeat the steps above.

To unlock the bootloader go to your adb folder open up a command line and type

adb reboot bootloader

When it boots to a mostly black screen with a tiny lil paragraph describing fastboot and giving some instruction type

fastboot flashing unlock


fastboot oem unlocck

From there your done for now with fastboot. Lets go ahead and type fastboot reboot.

A developer here who was trying to unbrick his lg phone ended up hacking the program LGUP and found out a way to download to different partitions of the phones memory. The option called partition dl will allow us to flash a rom to the phone with out flashing the aboot partition which holds our working fastboot mode. You could even change your phone from a aristo 2 to a fortune 2 or k8 or any number of combinations as long as you do not ever flash aboot.

Warning! Warning! Warning! Warning! Warning!

Just a reminder. If you flash the aboot of anothet cv1 device to your phone it will immediately go dead and will be bricked under Qualcomm HSUSB 9008 mode which at this point in time there is no fix for.

Now you will need LGUP dual mode and since we are using a cv1 device go over to tecknights Aristo 2 page grab LGUP dual mode from there and thank him for all his hard work.

While your there if you want root you will need to go ahead and grab his twrp 4 cv1 devices with oreo kernel from his tutorial on flashing a prerooted oreo rom and port it over to the K8+ or not or i may have it posted here. Either way you will need it soon.

Now download the LG firmware extractor and pull the boot.bin from the oreo rom you are using to upgrade your device to and rename it to boot.img then put it in a dedicated folder in external storage.

Download the latest version of magisk manager put it on your external storage sd card with your oreo boot image.

Now lets flash our K8+(2018) X210ULM to Android 8.1 OREO.

Plug your phone into your windows pc and start LGUP dual mode Dev. When it loads your device hit select and the fladhing screen will appear with several more options than the LGUP your probably used to working with. Click the circle next to

Partition DL

Now go and choose the rom you want to flash and check every partition except aboot. Then hit ok. When it gets done it will reboot into Oreo and you will still have your boitloader is unlocked screen warning upon boot.

If not you did something wrong. Reflash nougat read the directions again and reflash the oreo rom with every partition except aboot. Remember do not flash aboot. If you do you will lose your working fastboot.

You now have a cv1 device that not only has fastboot mode but it can also flash.

Now for root go to settings and set up your developers options and this time you will notice that the oem unlock switch is greyed out in the unlock position.

Now install magisk manager and choose the install by picking a file and patching it. When it gets done you will find it in internal storage Download folder. Now hook plug your phone back into the pc and place your TWRP 4 CV1 DEVICES w OREO KERNEL and magisk patched image into the adb folder and rename them recovery.img and boot.img and open up a commandline there.

Now type

adb reboot bootloader

fastboot flash boot boot.img

fastboot flash recovery recovery.img

fastboot reboot

Upon booting go to magisk and let it setup up the enviroment and reboot then before rebooting to twrp go ahead and go to settings and Downloads in magisk and install TWRP helper. Then go do not reboot but go up to modules and hit the reboot to recovery option. It should now reboot to twrp where you can now mount your partitions then make a back up then check those mounts again and reboot to system.

Thats it. Your done.


This can be done with any cv1 device that does not have an ARB value on before you start flashing. You upgrade an Aristo 2 to Oreo as well as a Fortune 2. The only stipulation is that you choose firmware with an ARB value of 0 and start with a device with a firmware that has an ARB value of 0.

Ive heard that one could possibly change an Aristo 2 to a Fortune 2 and a Fortune 2 to a K8+ or vice versa but im not brave enough to try.

Please be sure to thank Tecknight for his work with the CV1 and you dont have thank me but it would nice if some one did.
8th February 2020, 07:10 AM |#2  
OP Member
Thanks Meter: 7
Maybe i said i would post my recovery and rooted boot images. Maybe i didnt. Well i did i say i might. So any way these are my images. One magisk rooted-boot.image for the Lg LM-210ULM ONLY. This image is only to be used with K8+ running oreo. Do not use with nougat.


We also have a TWRP image for K8+ Lg LM-X210ULM android 8.1 Oreo. while this image should work for any android 8.1 cv1 device, its for android 8.1 only and could cause a bootloop if used for a 7.1.2 nougat device.

The recovery i ported over myself from teknights oreo version for cv1 devices. Why did i not just use his since most cv1 devices can use the same recovery? Well when i first started rooting this device i did but had some issues with my device feeezing at the K8+ screen. Also i had to set the system.img to ext4 or no mounting and i had to set firmware to vfat as well. Data was changed to ext4 since every time twrp was started i would have to wipe a reformat it.

Never had a problem where i had to change any thing in the recovery.fstab before but once those changes were made i had no more boot loops, mounting or formatting issues and it works without fail now.

Im including the no verity opt encrypt flash zip too. Dont forget to flash the first time you boot twrp or you might have a bad day.

Edit:::: since i pulled these images using flashify after flashing the no verity zip and also flashing the twrp storage helper you may not need to use flash zip or module yourself but i dont think it would hurt.
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