In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/sbin/fixup-mac-address line 2:

. /lib/functions.sh

  ^---------------^ SC1091 (info): Not following: /lib/functions.sh was not specified as input (see shellcheck -x).

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/sbin/fixup-mac-address line 3:

. /lib/functions/system.sh

  ^----------------------^ SC1091 (info): Not following: /lib/functions/system.sh was not specified as input (see shellcheck -x).

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/sbin/fixup-mac-address line 39:

	local message="$1"

        ^-----------^ SC3043 (warning): In POSIX sh, 'local' is undefined.

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/sbin/fixup-mac-address line 40:

	local default="$((! ${2:-0}))"

        ^-----------^ SC3043 (warning): In POSIX sh, 'local' is undefined.

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/sbin/fixup-mac-address line 42:

	echo -n "$message "

             ^-- SC3037 (warning): In POSIX sh, echo flags are undefined.

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/sbin/fixup-mac-address line 43:

	read opt

        ^--^ SC2162 (info): read without -r will mangle backslashes.

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/sbin/fixup-mac-address line 70:

	set -- $(echo "$NEW_MAC" | sed 's,:, ,g')

               ^-- SC2046 (warning): Quote this to prevent word splitting.

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/sbin/fixup-mac-address line 72:

	set -- $(gen_mac | convert_hex)

               ^----------------------^ SC2046 (warning): Quote this to prevent word splitting.

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/sbin/fixup-mac-address line 73:

	set -- $(printf %02x $(( (0x$1 & 0xfe) | 0x02 ))) $2 $3 $4 $5 $6

               ^-- SC2046 (warning): Quote this to prevent word splitting.

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

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

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

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

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

Did you mean: 

	set -- $(printf %02x $(( (0x$1 & 0xfe) | 0x02 ))) "$2" "$3" "$4" "$5" "$6"

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/sbin/fixup-mac-address line 80:

echo -ne "\x$1\x$2\x$3\x$4\x$5\x$6" | dd of=$part conv=notrunc bs=1 count=6 seek=$offset 2>/dev/null

     ^-^ SC3037 (warning): In POSIX sh, echo flags are undefined.

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

Did you mean: 

echo -ne "\x$1\x$2\x$3\x$4\x$5\x$6" | dd of="$part" conv=notrunc bs=1 count=6 seek=$offset 2>/dev/null

For more information:

  https://www.shellcheck.net/wiki/SC2046 -- Quote this to prevent word splitt...

  https://www.shellcheck.net/wiki/SC3037 -- In POSIX sh, echo flags are undef...

  https://www.shellcheck.net/wiki/SC3043 -- In POSIX sh, 'local' is undefined.