Xiaomi Redmi Note 7
Manufacturer

Xiaomi

Name

Redmi Note 7

Identifier

xiaomi-lavender

System Type

android

SoC

qualcomm-sdm660

Architecture

aarch64-linux

Source

Mobile NixOS repository

Builds

Hydra (default build)

Building

This will build the default output for your Xiaomi Redmi Note 7.

$ nix-build --argstr device xiaomi-lavender -A build.default

Installation

The device will need to be booted in its bootloader, or fastboot, mode. The boot image can be installed using the following command, assuming it was built using the previous command.

$ result/flash-critical.sh

If you have a system image (system.img) built, you can use fastboot to flash it to the device. Note that it might be too big to fit over the system partition. In such case, it can be flashed on the userdata partition.

Warning
 This will erase everything on the partition. Additionally, the common backups methods, e.g. TWRP, will not backup the userdata partition. 
$ fastboot flash userdata system.img

Device-specific notes

fastboot oem getlog

This is the first device, and possibly the only device, known to ship with the oem getlog fastboot command.

This is not a trivial command to use, but it is extremely useful as it allows side-stepping the need to boot in a known working system to use the ramoops console.

The output of the command is a jumble, but is still usable for figuring out early boot issues. It is much better than having to rely on a booted system to get the information, but still not as good as having a dedicated serial access.

Example usage follows.

 $ fastboot oem getlog 2>&1
(bootloader) [    0.000000] Booting Linux on physical CPU 0x0
[    0.000
(bootloader) 000] Initializing cgroup subsys cpuset
[    0.000000] Initi
(bootloader) alizing cgroup subsys cpu
[    0.000000] Initializing cgrou
(bootloader) p subsys cpuacct
[    0.000000] Initializing cgroup subsys
(bootloader) schedtune
[    0.000000] Linux version 4.4.153 (nixbld@loca
(bootloader) lhost) (gcc version 4.9.4 (GCC) ) #2 SMP PREEMPT Sat Nov 23
(bootloader)  20:31:33 UTC 2019
[    0.000000] Boot CPU: AArch64 Process
(bootloader) or [51af8014]
[...]

As the output of the command is on stderr, here’s how to output to a file.

 $ fastboot oem getlog > log.txt 2>&1

It is unknown if there are ways to make the output better.