Troubleshooting General Boot Issues

Top 5 Gotchas

  1. Get a good power supply capable of 1.5A or higher. Our CC boards typical use around 1.0A, each USB device use somewhere between 0.1A to 1A. The cable and connector quality and seating is as important as the power supply. If your board spontaneously reboots without any error message, it’s a power problem.
    a) If planning to use a spinning hard drive or SSD, put a powered hub between the board and the device as they exceed normal USB power budget.
    b) For power supplies where the cable is not integrated and requires a USB Type A cable, there may be a sufficiently high voltage drop over the wire depending on the wire gauge to affect deliverable power.
    c) Transient voltage drops will cause stability issues when running system loads. If your application or system is unstable, check the 5V pin with an oscilloscope. Voltage swings indicate poor power delivery.
  2. Get a good MicroSD card with at least 20MB/s sequential write speed. Slow MicroSD cards will result in a poor experience. Sometimes a slow MicroSD card means the flash cells are dying and the card needs to be replaced. Our software will check for MicroSD card data corruption and switch to read-only mode to prevent further damage to your data. It is recommended to backup your data and replace the card when this happens.
  3. Make sure you use proper tools to flash correctly. Incorrect images or incomplete flash will not boot. We recommend running a verify pass to make sure the data is correctly written. Also make sure that the image file matches your board model. On Windows, make sure to show file extensions so you can tell if the file has been decompressed. Flashing a compressed image will not boot.
  4. Each image lists the username and password in the release notes on the download page. We spent time to write them, read them.
  5. Most of our images will update in the background (unattended-upgrade service from the distributions) on first boot so performance will be slow until the updates complete. You can speed this up by manually running sudo eatmydata apt dist-upgrade in a terminal before the update service runs.
  6. Failure to do these will result in a lot of wasted time as they account for 99% of user problems.

If you’re new to single board computers or coming from Raspberry Pi, there can be a few gotchas or conceptual differences to be aware of. We outline how the process works and how you can quickly figure out what the issue is.

The normal process flow is as follows:

  1. Download Compressed Image (eg. file+model.img.xz)
  2. Extract Compressed Image (eg. file.img)
  3. Flash Extracted Decompressed Image to Bootable Storage Medium (MicroSD card)
  4. Insert Bootable Storage Medium into Board
  5. Provide Sufficient Power to Board
  6. Board Boots u-boot Bootloader from Storage Medium
  7. u-boot Bootloader Loads EFI Bootloader (GRUB)
  8. EFI Bootloader Boots Linux
  9. Linux Boots systemd
  10. systemd starts services and applications
  1. Download Compressed Image
    a. Make sure to download the correct file for your board to get the correct bootloader. The +model suffix on the file name should match your board or it will not work.
    b. Make sure to check the SHA256SUM of the downloaded file to verify correctness.
  2. Extract Compressed Image
    a. Use a decompression tool to extract the uncompressed image.
    b. Skipping this step will result in an image that will not boot.
  3. Flash Extracted Decompressed Image to Bootable Storage Medium
    a. Make sure the bootable medium is glitch free by running verify on written data.
    b. Make sure flashing tool does not perform any skips or write optimizations.
    c. Flashing is not copying the file! Flashing writes the raw data to the disk while copying writes the data on top of a filesystem. Copying files will result in the board not booting at all.
    d. Etcher or Raspberry Pi Imager are known to not produce bit accurate data on occasion. If the MicroSD card is not flashed correctly, you will not get any HDMI output. See the individual board behavior guide at the bottom.
  4. Insert Bootable Storage Medium into Board
    a. Make sure the storage medium is not damaged. MicroSD cards can break if the board is installed or removed from cases without removing the card first. Hair-line fractures will cause short-circuit so do not try to use them if you notice any fractures or damage! Short-circuit can cause the card to get really hot and burn your skin.
    b. We recommend SanDisk and Samsung MicroSD because those brands have a history of making reliability products. There are knockoffs that appear on Amazon. Kingston, PNY, and other brands have put out unreliable products in the past so we do recommend them.
  5. Provide Sufficient Power to Board
    a. Make sure your power supply provides enough voltage and current for the board you are using. Boards cannot be powered from computer USB ports which usually only provide 500mA or 0.5A. Most boards need a minimum of 1.5A.
    b. Do not trust the label unless the power supply is from a reputable brand.
    c. Certain power supplies can cause problems if they exceed 5.5V and cause certain board features to stop working.
    d. Check for bent, damaged, or corroded pins and loose connections. They reduce deliverable power.
  1. Board Boots u-boot Bootloader from Storage Medium
    a. If you followed steps 1 through 5 correctly, the board should boot up. LEDs on the board will change if the bootloader is successfully loaded from the storage medium.

Please reference board specific guides for additional information and steps:


I have the S905X Le Potato, and have flashed and reflashed an 8GB Transcend SD card with the regular and light distro from your link. Decompressed and flashed with Win32DiskImager and Raspberry Pi Imager. The 905 goes thru a boot sequence, changes the screen to a solid color, then reboots. It never goes to an opening welcome screen or asks me for a password or anything. If I catch it in time I am able to select normal boot or recovery mode. After selecting one of these it goes to a solid color screen and then proceeds to reboot again and the process continues. What can I do?

Spontaneous reboots are usually caused by power issues. What kind of power are you using?

I had a generic usb adapter that i use for all my rpi’s. Ill try a different supply, and a fresh sd card. What power supply would you recommend, and running raspian would you recommend the full or light version?

“We recommend SanDisk and Samsung because those brands are have a history of reliability. There are knockoffs that appear on Amazon. Kingston, PNY, and other brands have put out unreliable products in the past so we cannot recommend them.”

Transcend is trash and their 8GB cards are dubious.

Any MicroUSB power supply will work that provides at least 1.5A and not just on the label.

Either image should work. For the lite image, remember that you need to setup the account before you put the MicroSD card in. See the Raspbian release notes.

Thanks. Still have the Transcend. I’ll be switching brands. That’s what I had. All is good. Switched powe supplies and all works well. Apparently my original supply was only 500ma… know better. Didnt even look. And to be fair I had been using it with a pi zero.
Thanks for your help and quick responses! Greatly appreciated.

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I also have a Le Potato (S905X) which does not boot from the flashed images. The red and blue lights come on and stay on. Is there a reference sheet for the led codes or the boot process?

Red and blue on AML-S905X-CC means no bootloader was loaded. Most likely that it was flashed incorrectly.

No, the wrong image was flashed corrected. Once the non-v2 image was flashed, then it now boots.

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Recently I purchased S-905X.
Have a known good 5V power supply.

This is my microSD:

I flashed using GNOME disk. Tried both Armbian and Raspbian.

When I power up I get solid red and blue lights, indicating that nothing booted.

Any idea why this could be the case? Is this microSDXC incompatible?

I am ordering a UART cable and another smaller SanDisk class 10 microSDHC.

We recommend grabbing a distribution from our website: Index of /ci/
These images are CI’ed so they are known to boot.

Armbian does not to my knowledge have CI integrated image tests. The builds could work or not work depending on the state of the Armbian codebase. It also uses ext4 which is less reliable on SBCs and prone to data errors.

MicroSD cards are generally compatible. It’s rare to have a compatibility problem. That said, we do have ones we recommend per the guides found all over this website.

Make sure you extract the image before flashing. Make sure you have the right image for your board and not the wrong board image.

Thank you. I will try the CI’d builds and double check everything.
I did indeed extract everything correctly and check that it’s the S905X.

Also, my system did not even appear to cross the boot stage (red and blue solid lights). Even if the OS had a problem wouldn’t you think it could actually boot?

Worst case, do you suggest I simply wire up a UART?

Also, my system did not even appear to cross the boot stage (red and blue solid lights). Even if the OS had a problem wouldn’t you think it could actually boot?

What is the image file name you are flashing? Are you sure it ends with +model.img.xz? Le Potato is aml-s905x-cc.img.xz.

Worst case, do you suggest I simply wire up a UART?

UART will tell you that it didn’t find the bootloader.

Hello Mr. Libre,

I tried with the correct image from the CI, and it works! Thank you so much.

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What is the baud rate for s905x for UART? I read on other forms that some PL2303 chips for uart may not work with these boards as well so I am trying to find out what my issue is while debugging.

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This helped me so much! Thank you!

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I have le potato (s905x), installed raspbian os on sd card (no gui) and enabled ssh. I have a wifi dongle connected and whenever I connect my external hard drive it does not boot up or more accurately I cannot shh since it has not booted up. I can see that the wifi dongle is not lit up and the eth port does not light up as well. If I disconnect my external drive it works fine. and if I connect the drive afterwards it works fine as well. I’m looking to boot up from my sd card and have the external drive for nas even on reboots. Any suggestions on what I’m doing wrong? Does it not have enough power going in? Or is it the boot sequence somehow getting messed up?

Please read the original post pertaining to power and external drives.