RPi Easy SD Card Setup - eLinux.org

SD cards
▪ If you have problems, check you have latest firmware version (described above)
▪ Some SD cards do not work on the R-Pi, so check the list of known SD cards.
▪ If you are having problems setting up your SD card you might want to start by
erasing it completely - especially if it has been used elsewhere and still contains data
/ partitions.
▪ Windows and Mac users can download a formatting tool from the SD
Association: https://www.sdcard.org/downloads/formatter_3/
▪ Reformatting cards is also easy to do in a digital camera.
▪ After writing the image to the SD card, verify that you can see the boot partition
when you insert the SD card into your computer. The partition should contain a
number of files, including start.elf and kernel.img. If you do not see these files on the
SD card, you have made an error writing the image file.
▪ If you are manually preparing your SD card on Linux or Mac OS using the dd
command, this operation will completely erase any existing data and partitions. Make
sure you write to the whole card (e.g. /dev/sdd) and not to an existing partition
(e.g. /dev/sdd1).
▪ If you have an sdcard that doesn't work with latest firmware, head over here
(http://www.raspberrypi.org/phpBB3/viewtopic.php?f=63&t=6093) .
▪ If you put the SD card into your PC in an attempt to write the R-Pi operating system
onto it, and the PC tells you the card is write-protected, even with the write-protect
tab in the correct, forward position, then you may have a faulty SD-card rewriter.
There's a common fault with many SD-card rewriters - The write-protect tab is
detected by a very thin, narrow metal strip, that is part of a switch. When the card is
inserted, the write-protect tab is supposed to push the strip and make/break the
contact, as needed. Unfortunately, these strips have a habit of getting stuck, because
they are mounted in a thin plastic channel, and only need to be deformed slightly
sideways to get jammed.
Luckily, if you have this problem, most built-in card readers are easy to pull apart and
repair; some users have even reported succesfully unjamming the switch with a blast of
compressed air from a can into the SD-card slot without having to dismantle anything.
You may also be able to temporarily get round the problem by putting the write-protect
tab in a half-way position - this pushes on a different part of the strip and may break the
contact - it's worth trying a few, slightly different positions. You could also use a USB-
SD card adaptor, which are cheap to buy.