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Lenovo Tab 4 8 (lenovo-tb8504f)

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Revision as of 22:12, 22 June 2022 by S0p0st (talk | contribs) (add photos section, xfce4 screenshot)
Lenovo Tab 4 8
A Lenovo Tab 4 8 running postmarketOS
A Lenovo Tab 4 8 running postmarketOS
Manufacturer Lenovo
Name Tab 4 8
Codename lenovo-tb8504f
Released 2017
Hardware
Chipset Qualcomm APQ8017
CPU 1.4 GHz Cortex-A53
GPU Adreno 306
Display 800x1280 IPS LCD
Storage 16GB
Memory 2GB
Architecture aarch64
Software
Original software Android 7.0
postmarketOS
Category testing
Pre-built images no
postmarketOS kernel 3.18.140
Unixbench Whet/Dhry score 1166.2
Features
Flashing
Works
USB Networking
Works
Internal storage
No data
SD card
No data
Battery
Works
Screen
Works
Touchscreen
Partial
Multimedia
3D Acceleration
Broken
Audio
No data
Camera
No data
Camera Flash
No data
Connectivity
WiFi
Broken
Bluetooth
Partial
GPS
No data
NFC
No data
Miscellaneous
FDE
No data
USB OTG
Works
HDMI/DP
No data
Sensors
Accelerometer
No data
Ambient Light
No data
Proximity
No data
Haptics
No data
Barometer
No data


Note This page is about WiFi-only tablet lenovo-tb8504f. For LTE tablet, see lenovo-tb8504x.

Contributors

  • Angus-g

Users owning this device

Unlocking

In developer options the allow oem unlock toggle may be unexpectedly disabled. In this case, try a software update to confirm latest (final) version, similar to tb-8504f_s001019_190909_row. The fastboot key combo is volume down + power. No device-specific information (e.g., bootloader version) is presented on the fastboot splash screen. fastboot getvar all shows some basic details. The standard unlock command fastboot oem unlock gives a warning and shows the correct command.

Installation

Install TWRP (3.2.3 and 3.3.1 are available). Format the System partition to prepare for the postmarketOS image. Either install from a recovery zip directly in TWRP, or use pmbootstrap flasher as usual.

Note: install from a recovery zip using sdcard or via sideload fail with the initramfs-extra not found splash screen.

Status

Using the LineageOS kernel (which is derived from Lenovo's open-sourced kernel), we can boot to a graphical display with USB networking. If CONFIG_USB_G_ANDROID is not set, it seems that there are a lot of errors regarding charging when connected via USB, and the boot doesn't get through to init. The touchscreen is detected, but the driver gets disabled in libinput due to a kernel bug.

Hardware details

Chipset

The chipset appears to be APQ8017, with an Adreno 300-series GPU. It seems to be very similar (at the devicetree level) to MSM8917. Neither of these currently have a mainline kernel effort. Wikipedia suggests the Snapdragon 425 MSM8917 is software-compatible with MSM8937.

The values are estimated strictly from software, not hardware, results (fastboot, adb, or twrp-3.3.1-1-TB8504 [unified 8504f/x)], using the commands given below.

chipset details (software-derived)

sample commands (software-derived)

CPU Tuning

According to cpufreq-info (cpufrequtils package), the chipset does indeed have a tiny frequency range, 960MHz - 1.4GHz. Benchmarks (ubench) show trivial differences in performance between the available frequency governors (default is performance), and all result in thermal throttling (frequency limiting).

Battery

Charging works, monitor via systool -v -c power_supply

Sensors

Output of sudo hwtest

hwtest output


Output of sensors (lm-sensors package):

sensors output

For reference, output of sensorssandbox (v1.8, f-droid):

sensorssandbox results

Photos

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See also