Xiaomi Redmi Note 8T (xiaomi-willow)

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Xiaomi Redmi Note 8T
Redmi Note 8T running firefox and weston-smoke (kapton tape holding UART in place)
Redmi Note 8T running firefox and weston-smoke (kapton tape holding UART in place)
Manufacturer Xiaomi
Name Redmi Note 8T
Codename xiaomi-willow
Released 2019
Category testing
Original software Android 9, MIUI 10
postmarketOS kernel 4.14.117
Hardware
Chipset Qualcomm SM6125 Snapdragon 665
CPU Octa-core (4x2.0 GHz Kryo 260 Gold & 4x1.8 GHz Kryo 260 Silver)
GPU Adreno 610
Display 1080 x 2340 IPS LCD
Storage 32GB, 64GB, 128GB
Memory 3GB, 4GB, 4GB
Architecture aarch64
Unixbench Whet/Dhry score 4168.2
Features
USB Networking
Works
Flashing
Works
Touchscreen
Works
Display
Partial
WiFi
Broken
Xwayland
Works
FDE
Mainline
Battery
3D Acceleration
Broken
Accelerometer
Audio
Bluetooth
Camera
GPS
Mobile data
SMS
Calls
USB OTG
Works



Contributors

Maintainer(s)

Users owning this device


Note

This device is quite similar to the Xiaomi Redmi Note 7 (xiaomi-lavender), and many of the issues were solved with steps from that device page, so if you're hacking on the 8T it's a good idea to read the xiaomi-lavender page closely.

How to enter flash mode

Unlocking the bootloader

As with any Xiaomi device, in order to unlock the bootloader you need to sign up for a Mi Account, register your device through the MIUI Settings app (requires a working SIM inserted, but only for a few moments), and wait a week. The official Xiaomi tool only runs on Windows, but XiaoMiTool V2 worked for me on Debian Linux. Be careful, it's a closed source jar!

Before you go further

You are strongly recommended to install TWRP and back up ALL partitions to a safe place! (you can adb pull the images from twrp)

Entering recovery

Hold Volume Up + Power until you see the recovery screen.

Entering fastboot

Hold Volume Down + Power until you see the fastboot screen.

Installation

  • Install pmbootstrap.
  • pmbootstrap -y zap; pmbootstrap init, choose xiaomi-willow as your device
    • firmware is currently needed for tianma touchscreen
    • weston is currently the only tested display server
  • pmbootstrap install
  • Enter fastboot, plug USB into computer
  • pmbootstrap flasher flash_kernel
  • pmbootstrap flasher flash_rootfs
  • pmbootstrap flasher flash_vbmeta
  • Reboot, sometimes fastboot reboot works, otherwise hold down Power until it reboots to system.
  • Hopefully weston comes up with postmarketos-demos.
  • ssh user@172.16.42.1

You can also use pmbootstrap flasher boot to boot the kernel/initramfs without flashing.

What's broken

  • Restarting the display server will fail (due to panel power issues?)

UART

Necessary: reasonably fine soldering iron tip, steady hand

Highly recommended: microscope, steadier hand

  • Disassemble the phone. Here's a decent video.
  • I spent way too much time heating up the rubber and trying to use a suction cup. The glue is quite strong, and after heating up the edges to unreasonable temperatures I still couldn't pull the glass off with a suction cup. The key is to heat up the bottom a bit (around 100-150C) and use an extremely thin piece of metal to slide in the bottom and tear the rubber a bit. Then you can keep heating the edges and work your way around the perimeter.
  • After removing the glass, remove the ~12ish green screws holding the upper panel in place. One is hidden under a sticker. Pop the panel off with more prying, as gently as you can but some force will be needed.
  • This is the end of disassembly, the test points are now exposed.
  • Solder as shown in diagram.
  • Test connectivity between everything to make sure there's no shorts.
  • Connect to your favorite UART adapter. It expects 1.8v, but I used this adapter that only goes down to 3.3v, and it hasn't bricked yet.
  • screen /dev/ttyUSB0 115200

Partition Table

xiaomi-willow:~# gdisk -l /dev/mmcblk0 # EXPANDME

GPT fdisk (gdisk) version 1.0.5

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.
Disk /dev/mmcblk0: 61071360 sectors, 29.1 GiB
Sector size (logical/physical): 512/512 bytes
Disk identifier (GUID): 14932C12-AAEA-7ACE-8D8F-C97EFAF3445D
Partition table holds up to 88 entries
Main partition table begins at sector 2 and ends at sector 23
First usable sector is 34, last usable sector is 61071326
Partitions will be aligned on 8-sector boundaries
Total free space is 6 sectors (3.0 KiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1              40              55   8.0 KiB     FFFF  switch
   2              56              71   8.0 KiB     A02C  ssd
   3              72             135   32.0 KiB    FFFF  secdata
   4             136             199   32.0 KiB    A040  limits
   5             200             263   32.0 KiB    FFFF  multiimgoem
   6             264             327   32.0 KiB    FFFF  multiimgqti
   7             328             455   64.0 KiB    FFFF  qupfw
   8             456             583   64.0 KiB    FFFF  qupfwbak
   9             584             711   64.0 KiB    FFFF  vbmeta
  10             712             839   64.0 KiB    FFFF  vbmetabak
  11             840            1095   128.0 KiB   FFFF  xbl_config
  12            1096            1351   128.0 KiB   FFFF  xbl_configbak
  13            1352            1607   128.0 KiB   FFFF  devcfg
  14            1608            1863   128.0 KiB   FFFF  devcfgbak
  15            1864            2047   92.0 KiB    FFFF  bk0
  16            2048            2303   128.0 KiB   FFFF  storsec
  17            2304            2559   128.0 KiB   A029  fsc
  18            2560            3071   256.0 KiB   A022  apdp
  19            3072            4095   512.0 KiB   A018  rpm
  20            4096            5119   512.0 KiB   FFFF  rpmbak
  21            5120            6143   512.0 KiB   A017  hyp
  22            6144            7167   512.0 KiB   FFFF  hypbak
  23            7168            8191   512.0 KiB   FFFF  keymaster
  24            8192            9215   512.0 KiB   FFFF  keymasterbak
  25            9216           10239   512.0 KiB   FFFF  cmnlib
  26           10240           11263   512.0 KiB   FFFF  cmnlib64
  27           11264           12287   512.0 KiB   FFFF  cmnlibbak
  28           12288           13311   512.0 KiB   FFFF  cmnlib64bak
  29           13312           14335   512.0 KiB   A02D  keystore
  30           14336           15359   512.0 KiB   FFFF  frp
  31           15360           16383   512.0 KiB   FFFF  catefv
  32           16384           17407   512.0 KiB   FFFF  uefivarstore
  33           17408           19455   1024.0 KiB  FFFF  abl
  34           19456           21503   1024.0 KiB  FFFF  ablbak
  35           21504           23551   1024.0 KiB  A01A  ddr
  36           23552           25599   1024.0 KiB  FFFF  bluetooth
  37           25600           27647   1024.0 KiB  FFFF  bluetoothbak
  38           27648           29695   1024.0 KiB  A01F  misc
  39           29696           31743   1024.0 KiB  FFFF  dip
  40           31744           33791   1024.0 KiB  FFFF  toolsfv
  41           33792           35839   1024.0 KiB  FFFF  catecontentfv
  42           35840           39935   2.0 MiB     FFFF  imagefv
  43           39936           44031   2.0 MiB     FFFF  imagefvbak
  44           44032           48127   2.0 MiB     FFFF  uefisecapp
  45           48128           52223   2.0 MiB     FFFF  uefisecappbak
  46           52224           56319   2.0 MiB     FFFF  cateloader
  47           56320           60415   2.0 MiB     A027  modemst1
  48           60416           64511   2.0 MiB     A028  modemst2
  49           64512           71679   3.5 MiB     A012  xbl
  50           71680           78847   3.5 MiB     FFFF  xblbak
  51           78848           87039   4.0 MiB     A016  tz
  52           87040           95231   4.0 MiB     FFFF  tzbak
  53           95232          103423   4.0 MiB     FFFF  mdtpsecapp
  54          103424          111615   4.0 MiB     FFFF  mdtpsecappbak
  55          111616          127999   8.0 MiB     FFFF  spunvm
  56          128000          131071   1.5 MiB     FFFF  bk1
  57          131072          163839   16.0 MiB    A021  devinfo
  58          163840          180223   8.0 MiB     FFFF  logfs
  59          180224          200703   10.0 MiB    A02A  fsg
  60          200704          233471   16.0 MiB    FFFF  metadata
  61          233472          262143   14.0 MiB    FFFF  bk2
  62          262144          294911   16.0 MiB    FFFF  oops
  63          294912          344063   24.0 MiB    FFFF  dtbo
  64          344064          393215   24.0 MiB    FFFF  dtbobak
  65          393216          458751   32.0 MiB    FFFF  mdtp
  66          458752          524287   32.0 MiB    FFFF  mdtpbak
  67          524288          589823   32.0 MiB    FFFF  dsp
  68          589824          655359   32.0 MiB    FFFF  dspbak
  69          655360          786431   64.0 MiB    A026  persist
  70          786432          917503   64.0 MiB    A026  persistbak
  71          917504          983039   32.0 MiB    8300  logo
  72          983040         1114111   64.0 MiB    A036  boot
  73         1114112         1245183   64.0 MiB    FFFF  bootbak
  74         1245184         1376255   64.0 MiB    FFFF  splash
  75         1376256         1507327   64.0 MiB    FFFF  logdump
  76         1507328         1638399   64.0 MiB    A025  recovery
  77         1638400         1900543   128.0 MiB   A01C  rawdump
  78         1900544         2162687   128.0 MiB   FFFF  minidump
  79         2162688         2949119   384.0 MiB   FFFF  exaid
  80         2949120         3473407   256.0 MiB   0700  modem
  81         3473408         3997695   256.0 MiB   FFFF  modembak
  82         3997696         4784127   384.0 MiB   A039  cache
  83         4784128         4816895   16.0 MiB    FFFF  gsort
  84         4816896         6914047   1024.0 MiB  8300  cust
  85         6914048        10059775   1.5 GiB     A038  vendor
  86        10059776        19496959   4.5 GiB     A038  system
  87        19496960        61071326   19.8 GiB    A03A  userdata

Additional Info

Info from the Note 7 port that also applies to the 8T:

Kernel config

  • Disabled CONFIG_RNDIS_IPA because it panics at boot if CONFIG_USB_CONFIGFS_RNDIS is set. IPA seems to be an IP offload IC (?) that will route RNDIS straight to the modem with RMNET (?) over BAM (?).

See also