you know why when upgrading a switch IOS via ftp, sometimes there is a WS-C3750X-24P-L folder created in the flash for the new firmware automatically, and sometimes dont.
I just transfered a .bin file to the new switch and noticed it was copied on the root folder of the flash. Reloaded the switch and all is ok.
Switch#dir
Directory of flash:/
2 -rwx 2741 Mar 1 1993 00:16:37 +00:00 config.text
3 -rwx 14606784 Mar 14 1993 23:23:00 +00:00 c3750e-ipbasek9-mz.122-55.SE8.bin ->>>>> New IOS
4 -rwx 3096 Mar 1 1993 00:16:37 +00:00 multiple-fs
5 -rwx 1934 Mar 1 1993 00:16:37 +00:00 private-config.text
6 drwx 512 Mar 1 1993 00:07:09 +00:00 c3750e-universalk9-mz.122-55.SE5 ->>>>> Old IOS
If you do the recommended upgrade process of "archive download-sw", the script will create a temporary folder called "update". After the entire process is complete, the script will rename the "update" folder to what you always see.
If you WS-C3750V2-48TS-S do the upgrade of copying the BIN file to the appliance, no sub-directory is created.