Hash: SHA256


tl;dr: finally I went the easy and straight forward way from armbian,
including their kernel (sources) repo, as done similarly several times
before with some r'pis and raspbian: 

    - copy Armbian_19.11.3_Odroidxu4_stretch_legacy_4.14.150.img to
      sdcard, mount to treat NIC issues as mentioned below.
    - boot sd card, log in, apt dist-upgrade, install and run
      debfoster (-i), reboot. 
    - change apt sources.list from "debian stretch" to "devuan
      ascii", while keeping the armbian firmware and kernel repos
      resp. pointing them to "stretch":
        deb http://deb.devuan.org/merged ascii main
        deb http://deb.devuan.org/merged ascii-security main
        deb http://apt.armbian.com stretch main stretch-utils
    - apt update, upgrade, dist-upgrade.
    - install sysv-init, install and enable dropbear, disable the
      openssh-server init script, reboot. 
    - purge systemd and leftover openssh-server dependencies
      (including libsystemd0).

clone sdcard to emmc:

    - dd sdcard to compressed image, copy image to network share
      (or to sdcard's filesystem), boot sdcard, dd image to emmc. 
    - run /usr/sbin/nand-sata-install, toggle the xu4's boot
      selector (hardware) switch and re-boot with sdcard removed.

install and configure services:

    - nginx: I was surprised not to find any reasonable way to
      http-upload a nested directory structure, preserving the
      hierarchy (also, php-fpm had pulled in libsystemd0;) Thus:
    - dpkg -P php-fpm && debfoster && apt install vsftpd
    - done.


before I had tried:

first run with devuan_ascii_2.0.0_armhf_odroidxu4.img:

- - the system boots fine (as the logs will show later), but the NIC
  does not come up (and my hdmi-to-dvi adapter is not
  supported): /etc/network/interfaces file is configured for eth0, but
  a udev-rule renames the USB-connected eth0 to enxMACMACMACMAC. 

- - playing with net.ifnames=0 in /boot/boot.cmd and a MAC based
  70-persistent-net.rules do not solve the issue, but after some
  fscking the sdcard I get ssh access: keeping the new
  70-persistent-net.rules in /lib/udev/rules.d/ while removing
  73-usb-net-by-mac.rules, 75-persistent-net-generator.rules and
  80-net-name-slot.rules fixes the issue reliably (as
  editing /etc/network/interfaces probably would have done, too). 
- - short delight, then modprobe ip_tables: module not found.

then arm-sdk with defaults:

- - building finishes smoothly, but besides the kernel (arm-sdk pulled
  4.14.160), the result is identical to the precompiled image: after
  fixing NIC naming and logging in, there is still no ip_tables module
  available.

and later arm-sdk with armbian 19.11.3 "buster legacy 4.14.150" kernel
config (which has the iptables modules enabled):

- - same as before: (ifnames and) no iptables. uname shows a 4.14.48
  kernel, while under /lib/modules there is a 4.14.160 directory
  structure. transplanting kernel, modules and dtb from
  Armbian_19.11.3_Odroidxu4_buster_legacy_4.14.150_minimal.img still
  results in booting to 4.14.48. I wonder if I'd need to get into U-Boot
  and/or determining the physical location of the zImage file? After a
  quick look through the webs I decide not to so and ->tl;dr


libre Grüße,
Florian


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