Thx guys.
The init 4 or init 3 commands have no effect because the enigma2 process is not running.
I added to the "enigma2.sh" as well as to the "enigma2_pre_start.sh" scripts, new line at the beginning of the scripts:
#!/bin/sh
echo "[$(date '+%Y-%m-%d %H:%M:%S')] Shell script enigma2.sh was started" >> /tmp/e2_startup.log
However, no response. These two scripts do not run at all when booting the system (no record and no file "/tmp/e2_startup.log" was created).
It is unnecessary to test the functionality of the "enigma2.sh" script itself, which ensures the start of the enigma2 process / binary. This script still works and also starts Enigma - but only if I start it manually via SSH or Telnet connection. I wrote in the query that this "enigma2.sh" script after boot is not started, so why do you advise me to check if it starts at all ?
The error will be deeper somewhere - I think it's a system error. This error could have occurred (I only assume), for example, by interfering with the OpenMultiboot plugin in the Linux boot process. I really don't know where the real cause might be.
EDIT:
If I start Enigma via SSH with ENIGMA_DEBUG_LVL=4 and then stop the Enigma (CTRL + C shortcut), then the init 3 and init 4 commands have meaning and stop / start the whole Enigma. However, immediately after booting the set-top box, the init 3 and 4 commands have no effect because the enigma2 process is not running yet.
Edited by s3n0, 3 September 2020 - 09:00.