This is why I explain what everything does in my instructions..

sfdisk formating

what the lines mean are
start,end,type

so
,300,6
starts at the earliest spot(the begining of the card if this is the first parititon) ends at 300 (by default thats 300 kb.. run sfdisk with -uM to use Megabyte units.. uM get it.) and the 6 designates a FAT filesystem

Here is how I do my 2gig card

... actually just gonna copy and paste from my blog



Start the app with this command

sfdisk -uM /dev/mmcblk0

the -uM means display and accept Megabyte units, and you remember that /dev/mmcblk0 is your internal card

Now once your in there you need to setup 4 partitions.. well really just two but its gonna make you set up 2 empty ones too.. don't worry it will make sense.

I am going to use my card as an example, you can modify fairly easily. I have a 2 gig sd card. I am going to give 356 megs to my first partition for use by the applications for music and files and what not, and approximately 1.6 gigs for my rootfs(where the os and applications go). I am going to show all for lines of entry, then explain them.

,356,6
,,L
,,
,,

Ok, sfdisk is configured with three items per line sepearted by ",". The first item is the starting point. We leave it blank to use default, or the next point in line. The second spot is the ending spot. In the first line I defined it to stop 356 megs into the card and in the second left it blank because I wanted to use the rest of the space. The third spot is for filesystem type. 6 is a fat16 type and L is a linux partition type(also called a type 83). The last two lines are completely empty because there is no where to start, and no where to end because there is no more space. When prompted to write the information you can type y. Don't worry about any warnings.. its an old format tool and not aware of the advances in linux.