Firewall soft version upgrade is a common service content, but the flash room of firewall takes itself is limited. Must delete the old soft package before uploading the new soft package. Remain room is not reduced and new soft package cannot be uploaded either when deleting the flash files in firewall using delete command.
Add the delete downright parameter after delete command, i.e. delete /unreserved flash:/xxx，delete the files downright, avoid to format all the flash room by format command.
Flash files were just put into recycle bin when using delete command to delete them. And the recycle bin takes the flash room too.