In /logs/firmware/patool_extraction/rootfs.img_unblob_extracted/rootfs.img_extract/0-50593792.squashfs_v4_le_extract/usr/html/axis-cgi/file_upload.cgi line 3:

. /lib/rcscripts/sh/error.sh

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

In /logs/firmware/patool_extraction/rootfs.img_unblob_extracted/rootfs.img_extract/0-50593792.squashfs_v4_le_extract/usr/html/axis-cgi/file_upload.cgi line 4:

. /lib/rcscripts/sh/integer.sh

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

In /logs/firmware/patool_extraction/rootfs.img_unblob_extracted/rootfs.img_extract/0-50593792.squashfs_v4_le_extract/usr/html/axis-cgi/file_upload.cgi line 9:

	printf "Invalid parameter: $1\r\n"

               ^-------------------------^ SC2059 (info): Don't use variables in the printf format string. Use printf '..%s..' "$foo".

In /logs/firmware/patool_extraction/rootfs.img_unblob_extracted/rootfs.img_extract/0-50593792.squashfs_v4_le_extract/usr/html/axis-cgi/file_upload.cgi line 15:

[ "$CONTENT_LENGTH" ] && is_integer $CONTENT_LENGTH ||

                      ^-- SC2015 (info): Note that A && B || C is not if-then-else. C may run when A is true.

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

Did you mean: 

[ "$CONTENT_LENGTH" ] && is_integer "$CONTENT_LENGTH" ||

In /logs/firmware/patool_extraction/rootfs.img_unblob_extracted/rootfs.img_extract/0-50593792.squashfs_v4_le_extract/usr/html/axis-cgi/file_upload.cgi line 21:

path=$(file_upload -s $CONTENT_LENGTH -n 65536 -a 	--allowed-realms="$REALMS" --allowed-dirs="$DIRS" ) || ret=0

^--^ SC2034 (warning): path appears unused. Verify use (or export if used externally).

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

Did you mean: 

path=$(file_upload -s "$CONTENT_LENGTH" -n 65536 -a 	--allowed-realms="$REALMS" --allowed-dirs="$DIRS" ) || ret=0

For more information:

  https://www.shellcheck.net/wiki/SC2034 -- path appears unused. Verify use (...

  https://www.shellcheck.net/wiki/SC1091 -- Not following: /lib/rcscripts/sh/...

  https://www.shellcheck.net/wiki/SC2015 -- Note that A && B || C is not if-t...