How-To: Basic problems with SBCs, and how to troubleshoot them

by Daniel Franklin

You may know the feeling: You purchased that new single board computer and all of it’s accessories, waited for it to arrive, and now you have it in your hands. You get everything set up and plug it in and…. Nothing!!! Just a black screen and a rush of disappointment. Why won’t it boot? Why can’t you make an Internet/network connection? What are you doing wrong? In this blog we will discuss some of the most common problems and how to troubleshoot them.

Power issues

First, we will discuss the power issues that can arise. It is important to use the correct power supply for your SBC. Single Board Computers operate on low voltage and current, so it is especially important to deliver that power with the proper power supply. Many people assume that the old power supply from their cordless phone or mobile device will be adequate to power their SBC. Although you might get lucky and have a perfect match, most power supply units are very particular in the voltage and amperage they deliver, and under-/over-volting or under-powering your SBC can have disastrous results, rendering your SBC useless. if the voltage/amperage is insufficient, it will cause your SBC to not start, and too much voltage can fry your SBC. If your board’s LEDs will not illuminate, or if only the power LED does, then you might not be delivering enough, or too much power. Make sure that your power supply is rated to the exact power requirements of your SBC; Don’t throw your money away before you start your board.

Operating system issues

OK, so the power supply is the proper fit for your SBC, but it still won’t boot. All SBCs need an OS image, an operating system, just like all computers. This “image” must be written or flashed to a boot media, a microSD card or embedded multimedia controller (eMMC) which attaches to your SBC and provides the computer the information it needs to boot up. It is important to understand the differences between the different images for different SBCs, and the differences between the boot media they are flashed to. If your SBC has a kernel indicator LED (like the ODROID series) and it does not illuminate, we then can assume that there is an issue with your SBC interpreting the image. There can be many factors that can influence this. For example:

The ODROID-XU4 from HardKernel has a boot selector switch on one side of the board that must be positioned to either microSD or eMMC for the boot media used. Here are some troubleshooting questions to ask:

Is the image you are using compatible with your SBC?

• Images are ALWAYS board specific, as the information needed by an SBC differs with the architecture of the CPU and other components of the board (a Raspberry Pi image will not boot an ODROID, etc.)

Is the microSD or eMMC properly formatted?

• Hidden partitions and boot sectors can exist on media that has been previously used, and a traditional format may not remove them completely. Each board looks in specific regions of the memory for the information it needs. Many times, a microSD or eMMC will need to be manually formatted or “cleaned” to assure that all information has been erased and the entire memory is available, in order to assure that the image can be written to the specific region required.

If using a microSD card, is it a make and model that is compatible with your SBC?

• Unfortunately, all microSD cards are not created equal, and there are some brands and models that simply will not allow your board to boot. Some manufacturers, such as HardKernel and the Raspberry Pi Foundation have compiled a list of known working and non-working microSD cards for their SBCs.

If using an eMMC module, is the image that you are attempting to use compatible with the eMMC’s chipset?

• Some less recent images with an older version of the Linux kernel can conflict with the chipset of newer eMMCs, and vice versa. (For example the discontinued black eMMCs from HardKernel will not support later versions of Android and Ubuntu). In these cases, the kernel will need to be updated to a version that is supported, or a different eMMC module will be needed.

Connecting to Ethernet and WiFi:

Single board computers will have much less functionality without the ability to connect to the Internet or a network. So what is preventing your SBC from getting online? Here are the basic questions to ask:

• Is the LAN cable fully seated in the Ethernet port on your router and your SBC?

• Is your router providing a signal?

• Are the LEDs on your SBCs Ethernet port illuminated?

• Are the drivers for your router up to date? (If not, identify your router model, then search for and install the proper driver.)

WiFi connection:

• Is your WiFi module completely plugged in to your SBC?

• Is your wireless router providing a signal?

• Is your SBC recognizing your WiFi module (If you open a terminal and type “lsusb”, all peripheral devices connected to the SBC’s USB ports will be displayed.)

• If not recognized, are the WiFi module’s drivers installed and up to date? (WiFi devices that are not plug and play may need drivers to be compiled.)