Busybox's device manager mdev was originally meant to be set up by writing its
path to /proc/sys/kernel/hotplug before launching it, but that entry no longer
exists in Linux v5.4's procfs and mdev can be launched directly.
Since mdev is the element in the recovery initramfs that is in charge of
mounting all partitions where .swu packages can be found (update partition on
the eMMC/MTD, uSD and USB), checking for the existence of the hotplug entry in
the procfs before launching mdev in v5.4 was preventing the partitions from
being mounted, and causing all software updates to fail.
While at it, move the two second delay to before mdev is launched, so all
partitions can be mounted. Otherwise, some devices such as the USB might not
be ready when mdev is launched, causing its partition to not be mounted.
https://jira.digi.com/browse/DEL-7143
Signed-off-by: Gabriel Valcazar <gabriel.valcazar@digi.com>
48f8720a23