SD Cards not detected by Linux

Hi Robert,
I found that SD cards used and flashed with BBBw Images ( dd copied ) are not detected when plugged into SD card reader on Linux PC. The errors are mmc0: error -110 whilst initialising SD card
But if it is plugged in with a usb sd card reader, it can be detected. ( listed as /dev/sda, /dev/sda1)

Thank You,

Error 110 is: ETIMEDOUT

 #define	ETIMEDOUT	110	/* Connection timed out */

So while your device “detected” something it was unable to connect… Either worn or dirty pin’s on the connector, or a bad usb cable, or just a failing adapter.


Hi Robert,

Thank you for your prompt reply.
I tried several SD cards. It seems they are not worn or dirty pins. If those cards plugged into BBBw SD card reader on BBBw dev boards, they can be detected as /dev/mmcblk0 and /dev/mmcblkp1. lsblk command also lists those devices.
But If I plugged them into Ubuntu PC, dmesg shows many errors. ls, lsblk, lsusb commands show no devices.

If I plug them using USB sd card reader (plugged into usb port) into Ubuntu PC, it is listed as /dev/sdb. If fdisk /dev/sdb, it returns fdisk: cannot access '/dev/sdb: no media found.

Both usb sd card reader and sd reader are ok if a normal sd card is plugged in.

Best Regards,

Hi David,
what’s the density of your several Secure Digital (SD) cards you tried ?
It could be that just the physical size is too big to be recognised by your
system and therefore they cannot be initialized at all.
In the past there was a limit of 128kByte for some flash File Systems (FS).
Regards, Rolf

Sadly, with a -110 error, it will never get to that stage of the driver pipeline. Basically it’s detected a media device, but can not communicate with it.


Hi All,
My SD card is 32G. One is burned, and also it burned BBBw board. The sd card holder overheated. And the BBBw runs without sd card plugged in. Otherwise, it terminates kernel.

Other sd cards, may be also overheated. I don’t know for sure.

Best Regards,

That’s not supposed to happen… That it did is indicative of some manner of short circuit, which could be caused by a number of things. My guess would be a damaged/defective/counterfeit SD card, though a defect in the card connector causing incorrect connections to be made would be another possibility.

Fake flash memory products are not uncommon, and can range from being empty packages to having less than advertised capacity to being produced with chips that failed quality control testing, or that were never tested at all. It seems likely to me that cards produced with bad silicon would show symptoms like those that are described.

Hi Rick,

I have SanDisk Ultra Plus (several cards) , ordered through DIGIKEY, (or mouser ) .

Best Regards,

It’s been a few (many) years since we’ve had SanDisk (microSD/SD) products in stock.

I’ve had really good luck with these SLC based microSD cards from Swissbit, they are more expensive, but being SLC based, they are quite reliable…


Rob’s observation regarding DK’s stock of SanDisk products appears correct–I’d add that I’m not finding products with the mentioned branding listed at mouser either. If you could provide a specific part number, salesorder number, or invoice number for products purchased through DK, it’d be possible to look for reports of any similar issues from other customers.

Has the BBBw board in question been used with other SD cards successfully? If not, it would seem possible that there’s a defect on the board itself that’s causing the issue.

Hi Both,
I have ordered a few more BBBw, and I may have to order some SD cards. I will keep an eye on this and handle with care.

Best Regards,

Hi Robert,

I have order 3 more BBBw and a few SanDisk Edge 16G SD cards. But for unknown reasons, these new BBBw don’t detect SD cards anymore. They all worked for sometime, and suddenly stopped working. All these SD cards are good on my Linux Ubuntu PC.

I was using dd command to cp images between EMMC (/dev/mmcblk1) and SD card (/dev/mmcblk0)

Best Regards,

David Zhou

Ah @dzhou that sounds fishy… anything show up in dmesg? It’s not the ancient 3.8.13 kernel right?


Hi Robert,

Here is the dmesg related to mmc:

[ 0.980512] omap_hsmmc 48060000.mmc: Got CD GPIO
[ 0.981098] omap_hsmmc 48060000.mmc: Linked as a consumer to regulator.2
[ 1.008221] omap_hsmmc 481d8000.mmc: Linked as a consumer to regulator.2
[ 1.034859] omap_hsmmc 47810000.mmc: Linked as a consumer to regulator.1
[ 1.078754] mmc1: new high speed MMC card at address 0001
[ 1.084206] mmcblk1: mmc1:0001 M62704 3.56 GiB
[ 1.084826] mmcblk1boot0: mmc1:0001 M62704 partition 1 2.00 MiB
[ 1.085445] mmcblk1boot1: mmc1:0001 M62704 partition 2 2.00 MiB
[ 1.085797] mmcblk1rpmb: mmc1:0001 M62704 partition 3 512 KiB, chardev (245:0)
[ 1.091686] mmcblk1: p1
[ 1.146229] omap_hsmmc 47810000.mmc: card claims to support voltages below defined range
[ 1.158828] mmc2: new high speed SDIO card at address 0001
[ 8.017306] EXT4-fs (mmcblk1p1): INFO: recovery required on readonly filesystem
[ 8.017320] EXT4-fs (mmcblk1p1): write access will be enabled during recovery
[ 8.378087] EXT4-fs (mmcblk1p1): recovery complete
[ 8.381870] EXT4-fs (mmcblk1p1): mounted filesystem with ordered data mode. Opts: (null)
[ 11.519570] EXT4-fs (mmcblk1p1): re-mounted. Opts: errors=remount-ro
[ 831.332787] mmc0: card never left busy state
[ 831.337157] mmc0: error -110 whilst initialising SD card

at 831.333787, sd card is plugged in.

Thank you,
David Zhou

This is on the image:
AM3358 Debian 10.3 2020-04-06 1GB SD console

But I tried on buster 10, 2019-07-07 image. It is the same. It doesn’t boot from sd card, either.

Best Regards,

Hi Robert,

On another BBBw, plugin sd card, there is no message logged into dmesg.
All these BBBw were newly bought and working.


What kernel are you seeing issues with? uname -r ?

On all versions of kernels:

4.19.94-ti-r42 - console version
4.19.50-ti-r20 - buster 10

I found many posts can be found on this issue through google. Not just on BBBw, it is also on many other Linux platforms. It seems to me all answers are pointing to bad SD cards. But all these cards are good, at least they are R/W able on my Linux PC, and on our production boards. In my opinion, at least it on both ends (software driver and hardware ).

Weird thing is that one BBBw board was bad ( I had marked the SD card reader on the BBB, which was a few months ago, But now it is GOOD.) Believe or not, it is not I had mis-labeled or something. Because all of old BBBw went bad, I had to order a few more.

I think I am OK, now. because we have added SD card in our new rev boards.

Best Regards,