In /logs/firmware/patool_extraction/DUMP/mtdblock8_unblob_extracted/mtdblock8_extract/0-9650176.squashfs_v4_le_extract/etc/rc.d/init.d/create_certificate.sh line 2:

echo -n "starting create_certificate..."

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

For more information:

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