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[Umidigi One Max] Custom ROM, Modding, Rooting - Complete guide

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Thanks Meter: 24
By _cab13_, Senior Member on 24th June 2019, 12:10 PM
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Welcome to this guide, where I will guide you through rooting, flashing custom roms, and more, on our little Umidigi One Max !
WARNING : I am not responsible for your phone breaking or exploding during the night under your pillow. Please advice. If you cannot boot anymore, keep reading, your phone is NOT dead.

OFFICIAL ROM (Android 8.1)
The Umidigi One Max comes with Android 8.1 Out of the Box. Manufacturer has no plan on having 9.0 on the phone. That's why we root then ! Let's get into it.

Rooting the phone without unlocking it, or installing TWRP
Everything you'll do on this phone will NOT require a bootloader unlock. Note that this method is only in case you don't want to have your data wiped, or don't have access to an SD card (thus you cannot flash .zip in TWRP, except for ADB Sideloads)

What you'll need
IMAGE COURTESY OF bencebacsi @ Umidigi forums
  • In the unzipped ROM folder, find boot.img
  • Copy it to your phone storage using an USB cable or any other method
  • Open Magisk Manager, press install
  • Choose "patch boot image file"
  • Let magisk do it's job
  • Find the boot.img file you just copied
  • Copy the patched_boot.img back to your computer
  • Open SP Flash Tool
  • Open the "Download" tab
  • In "Scatter-loading file", press the folder icon and browse to the downloaded ROM folder. Choose the only file that shows up
  • Untick every box except for boot. There is a column called "Location" with a path, click on it to change to file.
  • Choose patched_boot.img
  • Click the "Download" button
  • Turn off your phone (not reboot) and connect is via USB
  • wait for the flash to succeed. Once done, unplug, boot, voila ! You got magisk !
Credits to topjohnwu for Magisk, what a great piece of work

Installing TWRP
Note that if you want to access the /data partition (internal storage), you'll have to wipe it ! If you do not need it, keep going, it won't wipe unless you want to.

What you'll needThis method is shorter and requires less downloaded files.
  • Turn off your phone
  • Run SP Flash Tool
  • Load the scatter file (see pictures above) you downloaded from the latest ROM (see above as well)
  • Untick everything except recovery
  • Change path to recovery.img to be the TWRP image
  • Click "Download" and plug your phone
  • After it's done, unplug, and press Power + Vol Up
  • You'll see three options appearing. That's how you'll get to the recovery. Use Vol Up to scroll, and Vol Down to select. Choose Recovery Mode !
  • TWRP should boot by now
  • EXTRA STEP : Make /data readable. You will need to format data (YOU'LL LOSE ALL YOUR DATA) (Wipe > Format Data > Type "yes") and after that, flash this zip :
You can now proceed to flash zips, including If you made /data readable, you can send it to your internal storage. If not, use an SD CARD or ADB PUSH / SIDELOAD.

Returning to stock to fix issues / brick
Use SP Flash tool but instead of unticking everything, tick everything. Note that USERDATA, if ticked, will clear your data.
Ticking only certain partitions may work if you got issues with magisk or system mods and are still on Official ROM. Flashing boot and system will remove Magisk. If you are on custom ROM, you can flash their system again to fix issues as well. Make sure to choose the right system.img in SPFT !

Installing GSI (Generic System Image) to get Android Pie 9.0
GSI takes advantage of Project Treble to create one system image that will work on most devices without issues due to a separate "vendor" partition. The One Max is Treble-compatible, but only up to 9.0 (No 10 Q for now)
This will allow you to get an AOSP experience, with it comes easy modding and theming, and less bugs, less chinese-spying (that's a thing apparently, but who cares really ? Not me to say the least)

GSI List
You can find a GSI List including bugs and download links in my other thread here :

Installing a GSI
You will need TWRP Installed. Check above if it's not done yet. You'll also need the, and I highly recommend you getting the disable-force-encryption zip
  • Start up by wiping /data in twrp (Wipe > Swipe the bar). It will not wipe the files in your internal storage (Music, Download, etc...). If you want to get access to /data in TWRP (which I highly recommend), you'll need to do a full format (Wipe > Format data > type yes).
  • Download a GSI (.img) and send it to your phone (Either using an SD Card, or adb push [file on computer] [destination folder]). Send Magisk and the disable-force-encryption zip at the same time.
  • Flash that system image using Install > Install Image > Browse to the .img file
  • Flash disable-force-encryption if you formatted /data (don't flash it if you didn't do that !)
  • Flash
  • Reboot and profit !
Note that there might be some issues with the GSI you choose. Most GSI suffers issues regarding Wifi Tethering/Hotspot. Other than that, check for my thread for issues regarding GSIs.
Some GSI require installation of GAPPS (Google Apps). Download a GAPPS zip and flash it at : (Choose ARM64 and 9.0)
If Installation fails, saying that system size is too small, go to (Wipe > Advanced Format > Tick "System" > Repair or change file system > Resize File System) and try flashing again.

Magisk FDE.AI
A great system manager. Saves a ton of battery without a performance hit. You need magisk installed. XDA Thread :
Fix SafetyNet not passing on custom ROMs/GSIs
SafetyNet will not pass by default on custom ROMs / GSIs.
Use Magisk Hide Prop Config :
Run 'su' then 'props' in a terminal emulator. Edit Device fingerprint, choose Pick a certified fingerprint. I recommend using Xiaomi Redmi Note 7, as it changes the status-bar to be notch sized.
Note that you may need to do this next fix to make 'su' work :
Root request not working with Magisk
On some GSIs, root requests will not show up. You need to move some vendor files over to system.
Use TWRP's File Manager (Advanced > File Manager) or Adb shell to copy theses files :
  • Code:
  • Code:
This will fix this issue until GSI / ROM creator fixes it in their ROM;

Enjoy your new phone ! Don't forget to say thanks to all the developers behind every project (not me ! I didn't do anything )
If you have any issues, feel free to ask questions !
See you on the other side
The Following 3 Users Say Thank You to _cab13_ For This Useful Post: [ View ] Gift _cab13_ Ad-Free
26th June 2019, 01:49 PM |#2  
Senior Member
Thanks Meter: 18
Downloaded phhusson's AOSP ROM

Extracted compressed image. Then...

Wiped Phone from TWRP w/ all three options Swipe, Formatted (Type "Yes"), and advanced wipe.

From TWRP went to:

Install > Install Image > Selected system-arm64-ab-gapp-su.img > Select Partition to flash image

From this screen it lists these partitions for selection:

-System Image

I select System image. It starts flashing. After it has finished, I go to reboot, and that is when TWRP states "No OS installed".

Am I downloading the wrong image file?

*********************EDIT************************* ***

Nevermind. I downloaded system-arm64-aonly-gapps-su.img.xz and it boots fine with gapps included
30th June 2019, 09:48 AM |#3  
OP Senior Member
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Thanks Meter: 24
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Exactly, you downloaded A/B image, not A-only.
16th July 2019, 06:14 AM |#4  
Thanks Meter: 2
Using phhusson's AOSP ROM. I got the root requests show up. However the superuser app is blank. Nothing shows in the list.
17th July 2019, 10:01 PM |#5  
Junior Member
Thanks Meter: 0
Request for a video to install GSI

I'm using Umidigi One Max Android 8.1 and want to upgrade to 9.0 . Can you please make a YouTube video showing how to install the GSI version I'd gladly appreciate it.
18th July 2019, 03:30 AM |#6  
Senior Member
Thanks Meter: 18
Over the last month or so, I've tried multiple GSI ROMs, and stock. I've rooted stock, and everything runs nicely, I just can't stand the lack of features. Even rooted on stock, Google Pay still works. If I install a GSI ROM like Havok, root it, gpay will not work. Not sure why it works on stock rooted with magisk, but not with other ROMs.

I'm looking for a hacked stock rom for the one max that:

A.) Can be rooted.
B.) Can still run gpay.
C.) Has a advanced restart option to boot directly into recovery.

D.) Displays the battery in the status bar as a percentage rather a symbol, and a clock with seconds option.

If I had those options, I would stick with stock. I can accomplish all those options with Havoc GSI ROM, I just can't get NFC/gpay to work.
1st August 2019, 12:55 PM |#7  
Junior Member
Thanks Meter: 3
how did you repair su binsaries after flasing (in twrp the vendor folder is empty)
everything else works
2nd August 2019, 03:20 AM |#8  
Junior Member
Thanks Meter: 8
@ _cab13_
thanks for tutorial

some comments/questions
Image shows MT6739 in phone image and scatter file of mt6739
My phone is MT6363 and appears to agree with online specs site such as

Am I looking at the wrong tutorial or umm have you grabbed images from another phone and forgot to say so?
13th August 2019, 11:59 PM |#9  
Junior Member
Thanks Meter: 0
Originally Posted by w1lh3lm3d

how did you repair su binsaries after flasing (in twrp the vendor folder is empty)
everything else works

You have to mount the folder system and vendor for reading and writing and you can copy it, this is in recovery mount
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