RPi Easy SD Card Setup - eLinux.org

Coloured splash screen
With recent firmware, a coloured splash screen is displayed after firmware (start.elf) is
loaded. This should be replaced by linux console a second later. However if the coloured
screen remains, it suggests the kernel.img file is failing to boot. Try replacing it with a
known good one.
Immediately after displaying the splash screen, the PI starts consuming a little more
current, if the PI resets at that moment its an indication that your PSU isn't able to deliver
the full current your PI requires, but dips its output voltage below a minimum when
loaded with the full current the PI needs.
Kernel Panic on boot
Text appears on screen, but then hangs with debug messages. This can be caused by USB
devices such as keyboards. Try again with nothing in the USB.
Raspberry Pi shuts down (or restarts) soon after booting up
This is caused by a power supply producing too low a voltage. See
#Troubleshooting_power_problems.
Pi boots sometimes but not always
With a known good power supply and known good SD card, the R-Pi boots occasionally,
but other times shows only a tiny green flicker from the "OK" LED and it fails to start,
[4] [5] [6]
even with no USB devices and no Ethernet. This has been reported several times
and remains an open issue. Low voltage or an improper SD card can cause it. Some SD
cards will work until they warm up slightly, and then fail [7] . When exposed to 21 C room
temperature the warmest part of an uncased working R-Pi should be 41 C [8] . The wiki