Having difficulties booting would mean that your SD Card is written the way it is supposed to be and the OS starts loading but doesn't proceed and most certainly doesn't prompt you for logging in.

How do you solve it?

  • 4
    More information would undoubtedly be required.
    – Jivings
    Jun 12, 2012 at 20:08
  • What (if anything) is up on the screen where it stops? Is there an error? Does the screen die (if so, see Tibor's answer below and try that first). Jun 12, 2012 at 20:16
  • This is a far too generic question - can you be more specific - what do you have, what have you tried, what do you expect? Jun 12, 2012 at 20:46
  • I added a very generic question to add a very good and extensive answer to it, with a lot of explanation. That's the idea of the beta version to receive lots of high-quality questions with good answers. Jun 13, 2012 at 16:27
  • Itehnological: You're question is probably a pretty good start to provide a "canonical answer" when the folks here will inevitably ask many variations of this question. The "canonical answer" is even encouraged by blog.stackoverflow.com/2012/05/encyclopedia-stack-exchange. But this site is simply too young to start hosting these overly-generalized questions so early in its life cycle. This may have to wait a bit. Jun 13, 2012 at 20:47

2 Answers 2


Possible Reasons:

  1. Your SD card doesn't contain a bootable image.

  2. Not efficient power supply
    Raspberry Pi's power requirements are as follows:
    - 5V
    - 700mA
    Make sure you choose a charger (power supply/adapter) which meets those requirements and also
    DO NOT TRY to power up your R-Pi using your computer's USB because it can provide no more than 100mA

  3. Using a non standard SD Card Linux is well renown for working slow with UHS-1 SD Cards. Actually in Raspberry Pi that's is not a problem because the ARM processor handles it appropriately. Well you still need to add some patches to the kernel on the SD Card. Follow these steps:

    1. Go to https://github.com/raspberrypi/firmware/tree/master/boot
    2. Download the following files:
    3. kernel.img
    4. arm224_start.elf
    5. Rename arm224_start.elf to start.elf
    6. Copy both files to the boot partition (FAT, ~60MiB) overwriting the existing files of the same names
    7. Done!

    *Note: You will need a Linux or Mac OS X to change the filesystem on the SD Card since it isn't readable by Windows! *

  • The boot partition IS readable by Windows, the others are not.
    – user13
    Jun 12, 2012 at 20:59
  • You may want to note that the 100mA limit (150mA for USB 3.0) is pre-negotiation, since most people assume that USB can supply 500mA. The wikipedia USB page has a good summary.
    – Mark Booth
    Jun 13, 2012 at 13:08
  • It is deceiving that computer USB ports cannot provide more than 100mA. "Charging" ports can provide even >1A.
    – user13
    Jun 27, 2012 at 15:22

Perceived SD errors are often a result of poor power supply. I would check the voltage between TP1 and TP2 pins and if it is below 4.5V, use a better cable or a better supply.

If you have network cable attached but the LED is not on (or going on and off), it is almost certainly a power issue.

A good cable is VERY important. If it is of poor quality, the voltage drop is too high.

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