In /logs/firmware/unblob_extracted/firmware_extract/DIR-600_fw_revb5_214b01_ALL_de_20130122/dir600b_v2.14_d1mg.bin_extract/1179788-3612812.squashfs_v4_le_extract/etc/events/reboot.sh line 10:

if [ "`xmldbc -g /runtime/device/layout`" != "router" ]; then

      ^-- SC2006 (style): Use $(...) notation instead of legacy backticks `...`.

Did you mean:

if [ "$(xmldbc -g /runtime/device/layout)" != "router" ]; then

For more information:

  https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...

[*] Source file reboot.sh