About Firmware?

[kasukidash]

i think main is wut makes the phone work, fs are the files such as pics, etc

[blkdragon]

main makes the phone work, contains code ESSENTIAL to the operation of the phone.

FS is the file system structure, so when you insert a new (non-formatted) m2 card or similar, the phone knows what files and folders to create, and where to create them so they're compatible with the phone.