[Letux-kernel] playing with PinePhone - rootfs, kernel etc.

[H. Nikolaus Schaller]

The biggest problem was to find out where the µSD slot is :)

You have to pop open the full back cover and then there is a tiny combined µSIM and µSD reader near the battery.

Then I looked up where to get a bootable Linux. I did choose Ubuntu Touch:
https://wiki.pine64.org/index.php/PinePhone#Ubuntu_Touch

I just did:

root at letux:~# wget -O - https://ci.ubports.com/job/rootfs/job/rootfs-pinephone/lastBuild/artifact/ubuntu-touch-pinephone.img.gz | gunzip | cat >/dev/sdb

and then the µSD looks like:

root at letux:~# ls -l /media/letux/ROOTFS
total 92
drwxr-xr-x   2 root root  4096 Dec 14 07:30 bin
drwxr-xr-x   2 root root  4096 Dec 14 07:59 boot
drwxr-xr-x   4 root root  4096 Dec 14 07:23 dev
drwxr-xr-x 109 root root  4096 Dec 14 08:00 etc
drwxr-xr-x   3 root root  4096 Dec 14 07:30 home
drwxr-xr-x  19 root root  4096 Dec 14 07:58 lib
drwx------   2 root root 16384 Dec 14 08:00 lost+found
drwxr-xr-x   2 root root  4096 Dec 14 07:21 media
drwxr-xr-x   2 root root  4096 Dec 14 07:21 mnt
drwxr-xr-x   3 root root  4096 Dec 14 07:29 opt
drwxr-xr-x   2 root root  4096 Apr 12  2016 proc
drwx------   2 root root  4096 Dec 14 07:30 root
drwxr-xr-x   8 root root  4096 Dec 14 07:29 run
drwxr-xr-x   2 root root  4096 Dec 14 07:30 sbin
drwxr-xr-x   2 root root  4096 Dec 14 07:56 script
drwxr-xr-x   2 root root  4096 Dec 14 07:21 srv
drwxr-xr-x   2 root root  4096 Feb  5  2016 sys
drwxrwxrwt   2 root root  4096 Dec 14 07:30 tmp
drwxr-xr-x  10 root root  4096 Dec 14 07:21 usr
drwxr-xr-x  11 root root  4096 Dec 14 07:30 var
root at letux:~# ls -l /media/letux/ROOTFS/boot/
total 19840
lrwxrwxrwx 1 root root      21 Dec 14 07:59 Image.gz -> Image.gz-5.4.0-pine64
-rw-r--r-- 1 root root 7454037 Dec 12 18:18 Image.gz-5.4.0-pine64
-rw-r--r-- 1 root root 3392125 Dec 12 18:18 System.map-5.4.0-pine64
-rw-r--r-- 1 root root     725 Dec 14 07:59 boot-dontbeevil.scr
-rw-r--r-- 1 root root     653 Dec 14 07:59 boot-dontbeevil.txt
-rw-r--r-- 1 root root     724 Dec 14 07:59 boot-pinephone.scr
-rw-r--r-- 1 root root     652 Dec 14 07:59 boot-pinephone.txt
-rw-r--r-- 1 root root     722 Dec 14 07:59 boot-pinetab.scr
-rw-r--r-- 1 root root     650 Dec 14 07:59 boot-pinetab.txt
-rw-r--r-- 1 root root     724 Dec 14 07:59 boot.scr
-rw-r--r-- 1 root root     628 Dec 14 07:59 boot.txt
-rw-r--r-- 1 root root  158964 Dec 12 18:18 config-5.4.0-pine64
lrwxrwxrwx 1 root root      33 Dec 14 07:59 dtb -> /usr/lib/linux-image-5.4.0-pine64
-rw-r--r-- 1 root root 4634987 Dec 14 07:59 initrd.img
-rw-r--r-- 1 root root 4634987 Dec 14 07:59 initrd.img-5.4.0-pine64
root at letux:~# 

Quite up-to date that it comes with a v5.4 kernel :)

U-Boot is very likely sitting in a hidden partition like for Udoo neo
or the Kobilino. fdisk says:

Device     Boot Start     End Sectors  Size Id Type
/dev/sdb1  *     1953 7812499 7810547  3.7G 83 Linux

So it does not look difficult to teach makesd to build a bootable µSD.
And teaching the Letux kernel to support CONFIG_ARCH_SUNXI.

My biggest barrier seems to be that it is ARM64 and I have no ARM64
toolchain in my kernel build setup... Maybe it can also run with 32 bit
like the RasPi?

Anyways I now need to test the µSD in the device.

BR,
Nikolaus