helping a friend. He says he tried to install a game into NAND but got an error. and corrupted installation files are using space in the nandThe folders to look for such files are
/install/
/usr/import/*/
Note that stuff in /install/ isn't trash but something you downloaded but didn't install. There are users doing this on purpose, so us cleaning /install/ would be a nightmare.
Files left at /usr/import/*/ should never happen, so open a bug report for that in case you know how to recreate.
what is the path to use in FTP To find & delete those files?