In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/etc/init.d/vsftpd line 4:

START=50

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

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/etc/init.d/vsftpd line 23:

	mkdir -m 0755 -p /var/run/vsftpd

              ^-- SC2174 (warning): When used with -p, -m only applies to the deepest directory.

In /logs/firmware/unblob_extracted/firmware_extract/1568982-13971496.squashfs_v4_le_extract/etc/init.d/vsftpd line 24:

	service_start /usr/sbin/vsftpd -olisten_port=${FTP_PORT:-21} -opasv_min_port=${FTP_DATA_PORT_1:-40000} -opasv_max_port=${FTP_DATA_PORT_2:-50000} -olocal_umask=0777 -ochroot_local_user=YES -oallow_writeable_chroot=YES

                                                     ^-------------^ 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: 

	service_start /usr/sbin/vsftpd -olisten_port="${FTP_PORT:-21}" -opasv_min_port="${FTP_DATA_PORT_1:-40000}" -opasv_max_port="${FTP_DATA_PORT_2:-50000}" -olocal_umask=0777 -ochroot_local_user=YES -oallow_writeable_chroot=YES

For more information:

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

  https://www.shellcheck.net/wiki/SC2174 -- When used with -p, -m only applie...

  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...