Samsung Galaxy J4 (samsung-j4lte)
 Samsung Galaxy J4, on postmarketOS boot splash screen | |
| Manufacturer | Samsung |
|---|---|
| Name | Galaxy J4 |
| Codename | samsung-j4lte |
| Model | SM-J400 |
| Released | 2018 |
| Type | handset |
| Hardware | |
| Chipset | Samsung Exynos 7570 Quad |
| CPU | 4x 1.4 GHz ARM Cortex A53 |
| GPU | Mali T720 |
| Display | 720x1280 IPS |
| Storage | 32 GB |
| Memory | 2 GB |
| Architecture | aarch64 |
| Software | |
| Original software | Android |
| Original version | 10 |
| postmarketOS | |
| Category | testing |
| Pre-built images | no |
| postmarketOS kernel | 3.18.140 |
This means that it cannot be selected in pmbootstrap.
| Flashing |
Partial |
|---|---|
| USB Networking |
Works |
| Internal storage |
Works |
| SD card | |
| Battery |
Works |
| Screen |
Works |
| Touchscreen |
Works |
| Multimedia | |
| 3D Acceleration | |
| Audio |
Broken |
| Camera |
Broken |
| Camera Flash | |
| Connectivity | |
| WiFi |
Works |
| Bluetooth | |
| Ethernet | |
| GPS | |
| Modem | |
| Calls | |
| SMS | |
| Mobile data | |
| Miscellaneous | |
| FDE | |
| USB OTG | |
| Sensors | |
| Accelerometer | |
| Magnetometer | |
| Proximity | |
| Hall Effect | |
| Haptics | |
| Barometer | |
| Power Sensor | |
Contributors
- manoedinata
Users owning this device
- Manoedinata (Notes: Normal condition.)
How to enter flash mode
Power + Volume Down + Home
In some cases, using power button to boot into Download Mode doesn't work. Instead, while pressing Volume Down + Home, connect the device to PC via USB. Don't release the buttons until you're in the Download Mode.
Installation
Use pmbootstrap to build your own installation image. The device configuration will also build firmware package, which contains required proprietary blobs for Wi-Fi.
Heimdall installation doesn't work. Use Installation_from_recovery_mode instead.
Known Working
- Touchscreen
- Screen & display
- Framebuffer (additionally with
msm-fb-refresherto refresh the screen) - Charging & battery status
- Wi-Fi (partially, with firmware package)
Notes
Wi-Fi
To enable Wi-Fi, these proprietary blobs are required to be loaded:
vendor/etc/wifi/mx
vendor/etc/wifi/mx140.bin
vendor/etc/wifi/mx140_wlan.hcfThese files are pulled and packaged already in firmware-samsung-j4lte pmaports package.
Framebuffer
Some patches are required for framebuffer to fix some issues, e.g. swapped color.
The kernel panics with null pointer dereference if running framebuffer-based or text interfaces with CONFIG_FRAMEBUFFER_CONSOLE, or if you want to display kernel console to the screen. So, none or console environment doesn't show anything.
 |
Newer DECON drivers as seen in newer devices e.g. Samsung Galaxy A51 (samsung-a51) also have similar issue, and can be fixed by keeping fb0 enabled. Could it be the same reason for our device? |