Cannot Boot From microSD Card, But microSD Reader Is Functional

General Discussion
1

I have a BBB w/ the TI AM3358. I cannot force it to boot from the microSD card no matter what I try. I am flashing images to the SD cards using balenaEtcher. The BBB was recently purchased, though I am not sure exactly what rev it is. But my understanding is I shouldn’t actually NEED to hold the boot button on later revs. However, this doesn’t work. I have also tried holding the boot button for every amount of time conceivable (three seconds, one minute, and every number in between).

The microSD port (and the multiple 32GB microSD cards I’ve tried) DO work: if I write a flasher image to the microSD card, it will load the eMMC from it no issues (as long as the size is under 4GB). But if I want to try an OS that is >4GB, my hands are tied.

I tried erasing the eMMC boot sector, and then trying booting from microSD again. No luck (with boot button or without). I’ve tried editing uEnv.txt to re-comment the flasher and repeated all of these steps. No luck.

Anyone have any idea what I’m doing wrong?

2

Plug in a usb-serial adapter into J9 header, then we can see what is going on the serial port.

3

I assume you mean P9? Know what pins exactly?

4

J6 on the BeagleBone pcb: Making sure you're not a bot! you can also use the rpi debug adapter’s serial: https://www.raspberrypi.com/products/debug-probe/

5

Ordered, thanks! BTW: it’s J1 on my board.

6

I find bb-image is really good now. I couldn’t get balenaEtcher to work at all, last time I tried it about a year go (and had to get a really old imager from sourceforge instead).

The situation you describe would also occur when trying to boot up from an image that wasn’t flashed correctly so eliminating balena from the equation is worth a go.

7

Thanks, but I have tried the BB Imager multiple times too with no luck. I format the 32GB SD card using BB Imager while it’s in my PC. I then move it to the BBB, and attempt to write an image to it, but immediately get a “Failed to Open SD Card” error.

8

Which OS Windows/Mac/Linux?

9

Windows PC running BB_Imager. Here is the error message:

2026-08-05T19:25:44.447731Z ERROR bb_imager_gui: Flashing failed with error: FailedToOpenDestination {
source: WindowsCleanError(
Output {
status: ExitStatus(
ExitStatus(
1,
),
),
stdout: “”,
stderr: "Clear-Disk : There is no media in the device.\r\nActivity ID: {a4294913-1dea-0003-d54a-29a4ea1ddd01}\r\nAt line:1 char:1\r\n+ Clear-Disk -Number 1 -RemoveData -Confirm:$false\r\n+

You can see it can’t find the SD card. But it doesn’t make sense that a flasher image on the SD card can be copied to the eMMC if that were the case.

10

@ayush1325 does that look like the “windows protection” error we saw last month?

11

It does seem like it. It doesn’t seem to occur in VM though (and not in all installs of windows either), so I am not exactly sure about trigger conditions.

We need to start pushing to ms store. I think that would avoid this particular issue since store signs things for us with a ms approved key for free. Just waiting for Jason to create a BeagleBoard store account.

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