In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/bin/board_detect line 7:

[ -d "/etc/board.d/" -a ! -s "$CFG" ] && {

                     ^-- SC2166 (warning): Prefer [ p ] && [ q ] as [ p -a q ] is not well defined.

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/bin/board_detect line 8:

	for a in `ls /etc/board.d/*`; do

                 ^-----------------^ SC2045 (error): Iterating over ls output is fragile. Use globs.

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

Did you mean: 

	for a in $(ls /etc/board.d/*); do

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/bin/board_detect line 9:

		[ -x $a ] || continue

                     ^-- SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean: 

		[ -x "$a" ] || continue;

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/bin/board_detect line 10:

		$(. $a)

                ^-----^ SC2091 (warning): Remove surrounding $() to avoid executing output (or use eval if intentional).

                    ^-- SC1090 (warning): ShellCheck can't follow non-constant source. Use a directive to specify location.

                    ^-- SC2086 (info): Double quote to prevent globbing and word splitting.

Did you mean: 

		$(. "$a")

For more information:

  https://www.shellcheck.net/wiki/SC2045 -- Iterating over ls output is fragi...

  https://www.shellcheck.net/wiki/SC1090 -- ShellCheck can't follow non-const...

  https://www.shellcheck.net/wiki/SC2091 -- Remove surrounding $() to avoid e...