Official Debian support

[moonwalkers]

just to clarify (I could be completely wrong - sorry not as experienced):

• debootstrrab sid to mmclk2p2
  
• chroot into mmclk2p2
  
• install additional packages (like linux-image-5.10.0-7-arm64 to get at least .38)
  
• you say "I also have `u-boot-menu` package installed, that automatically generates extlinux-style boot menu for u-boot." How so?
  

Sorry again for my ignorance

Off the top of my head (it's been a while), the installation I did was essentially these steps:

• create two partitions on eMMC using GPT partitioning, one starting on sector 64 and ending on sector 32767, 32704 sectors in size, and another starting at sector 32768 and until the end of the available eMMC space. The first partition is just a protective partition for u-boot (link to the version I used is above), second I formatted with ex4 and used whole for my Debian installation.
  
• mounted second partition in live microSD. Because I just wanted to fuck around, I manually downloaded and unpacked bunch of packages until I could get APT to work in a chroot, but standard debootstrap would've worked just fine too, and much faster.
  
• chroot into mmcblk2p2.
  
• install linux-image-arm64, which, if you're on Sid/Unstable, will pull in linux-image-5.10.0-7-arm64 as dependency and will generally keep your kernel up-to-date.
  
• install u-boot-menu. Adjust /etc/default/u-boot to your taste, run `sudo u-boot-update`. Check that you now have /boot/extlinux/extlinux.conf that points to your /boot/vmlinuz-5.10.0-7-arm64
  
• make sure to install network-manager before you attempt rebooting - without it you'll have hard time connecting to WiFi, and without WiFi you'll have hard time installing the rest of the packages.
  
• after getting successful boot and WiFi connection using nmcli I configured zram swap and at that point it was just the matter of installing the rest of the packages I cared about
  

Note that the steps above would initially yield a system with no GUI whatsoever, but you should be able to boot with terminal and WiFi, and that's really all you should need to get going.