porting.md

Porting - Using linux-me176c in other distributions

Most of the code in linux-me176c is not specific to one Linux distribution. In fact it is already being used for Android, Arch Linux and postmarketOS. This page explains how to apply it to an other Linux distribution.

Linux kernel fork (linux-me176c)

Most of the necessary patches for full functionality have been submitted upstream. However, the battery/charging drivers have been ported from the downstream stock (3.10) kernel. Even though they went through major cleanup already, they are not even closely in a state that is suitable for upstreaming.

This is why it is necessary to run a Linux kernel fork ("linux-me176c") for full functionality. Compared to other downstream kernel it only carries a couple of patches that can be easily rebased on top of newer kernel versions.

Usually, linux-me176c tracks the latest LTS kernel and is available from one of the branches in this repository.

Dependencies

Unfortunately, there are a few closed-source components required for full functionality. Some of them (e.g. me176c-acpi and CPU Microcode) will be running anyway through the BIOS. Therefore, replacing them with updated/fixed versions will not add new unfree code.

• me176c-acpi: For full functionality (e.g. touchscreen, Bluetooth, ...)
• Firmware:
  • linux-firmware (available as package for almost all distributions):
    • WiFI: brcm/brcmfmac43362-sdio.bin
    • Sound: intel/fw_sst_0f28.bin
  • Additional firmware from the ASUS stock ROM (UL-K013-WW-12.10.1.36-user.zip):
    • WiFI: /system/etc/nvram.txt -> brcm/brcmfmac43362-sdio.txt
    • Bluetooth: /system/etc/firmware/BCM2076B1_002.002.004.0132.0141_reduced_2dB.hcd -> brcm/BCM2076B1.hcd
• Userspace:
  • Battery Daemon (/sbin/upi_ug31xx in the boot.img ramdisk of the ASUS Stock ROM):
    May be needed for battery driver to work correctly. Appears to be used for calibration/backup purposes.
    • Running it avoids User space daemon no response spam in the kernel log.
    • Requires mounting the config partition at /config, although the mount point can be changed by using sed on the binary.
    • Example extraction: Arch Linux (AUR) me176c-firmware package
    • Example systemd service: Arch Linux (AUR) me176c-battery package
• CPU Microcode Update: Not included in Intel's Linux microcode update package.
  • Download: From platomav/CPUMicrocodes
  • Pack it into an initrd for use with the Linux CPU microcode updater.
  • Example package: Arch Linux (AUR) intel-ucode-byt-t-c0 package

Notes

See also: Tips and tricks (ArchWiki)

WiFi / Bluetooth

• WiFi / Bluetooth do not use the same MAC address as the stock (ASUS) system by default
• Bluetooth needs to be configured with an unique MAC address from userspace to make it work
• me176c-factory can be used to apply the ASUS WiFi/BT MAC address from the factory partition

Thermal

Consider setting up a Thermal Daemon (e.g. thermald) to monitor device temperature and to throttle the CPU performance early when the device gets too hot.

• Custom configuration for thermald is provided in this repository.