JeffZ123
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Ye Old unknown-block(179,2)

Mon Sep 09, 2019 12:36 pm

Does anyone know why some SD cards give unknown-block(179,2) while other's don't? For example, the SD cards I get from Microcenter work out of the box, but the SanDisk's I've been getting from Amazon stubbornly give unknown-block(179,2) - and i'm not buying the bargain basement one's either (today i'm using SanDisk 32GB MicroSD HC Ultra Uhs-1 Memory Cards.)

Here is the full message:

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Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,2)
.
Here is the process I perform on both SD's:

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1 - Format with SD Memory Card Formatter
2 - Burn latest Raspian image using Etcher, in this case "Raspbian Buster with desktop"
.
Following the same process above only changing the SD card (Microcenter vs SanDisk) yeild different results.

I've tried some of the fixes here, but no joy. I'm currently working around the situation by using Noobs to install Raspian on the SanDisk which works fine so this isn't a showstopper for me, but still puzzling and a bit frustrating that I don't know why this is happening or how to fix it =P

pcmanbob
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Re: Ye Old unknown-block(179,2)

Mon Sep 09, 2019 12:51 pm

I would suggest you test the SD cards you got from Amazon using H2testw to see if they are in fact fakes or low quality seconds.

https://www.softpedia.com/get/System/Sy ... estw.shtml
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procount
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Re: Ye Old unknown-block(179,2)

Mon Sep 09, 2019 1:08 pm

Note that Etcher performs a low-level bit-copy (like dd) which effectively formats and writes the data file content to the SD card at the same time.
This makes step 1 (formatting the SD card) totally redundant and unnecessary.
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scruss
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Re: Ye Old unknown-block(179,2)

Mon Sep 09, 2019 3:50 pm

Similar to H2testw, there's f3, which runs on a Raspberry Pi:

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sudo apt install f3
Its f3write/f3read command pair fill an SD with unpredictable data, then read it back. If the writes and reads don't match, you have a bad card.

Note that with Amazon purchases, you've got no idea what you're going to get.
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JeffZ123
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Re: Ye Old unknown-block(179,2)

Mon Sep 09, 2019 4:45 pm

procount wrote:
Mon Sep 09, 2019 1:08 pm
Note that Etcher performs a low-level bit-copy (like dd) which effectively formats and writes the data file content to the SD card at the same time.
This makes step 1 (formatting the SD card) totally redundant and unnecessary.
Cool thanks for the heads-up on that procount, good to know. I'll skip that step in the future. I'm testing the card with H2testw, i'll report back results in a bit.

JeffZ123
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Re: Ye Old unknown-block(179,2)

Mon Sep 09, 2019 6:56 pm

I had no errors with the sdcard using H2testw

Test finished without errors.
You can now delete the test files *.h2w or verify them again.
Writing speed: 17.9 MByte/s
Reading speed: 26.8 MByte/s
H2testw v1.4
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pcmanbob
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Re: Ye Old unknown-block(179,2)

Tue Sep 10, 2019 11:18 am

If your SD card passed the test but still cant write to block(179,2), then I as stumped.

An error like that would normally be because the card is faulty or a fake, but yours passed the test so should not be either,

have you tried flashing them again with raspbian and if they work now.
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procount
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Re: Ye Old unknown-block(179,2)

Tue Sep 10, 2019 11:36 am

From what little I have googled, the ',2' indicates a problem with partition number 2, maybe unable to mount it?

You seem to have some other SD cards that work, and I assume you have a USB SD card reader. So try running Raspbian on one of your other cards, inserting your faulty one (after Raspbian has been flashed with Etcher onto it) into the USB SD card reader. It should show up as /dev/sda1 and /dev/sda2.
You could try:

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sudo fdisk -l /dev/sda
to see what it reports. It should show the 2 partitions.
You could try checking the file system with

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sudo fsck.ext4 /dev/sda2
And try mounting it

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mkdir -p /tmp/2
sudo mount /dev/sda2 /tmp/2
Other than that, I've "not a clue".
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JeffZ123
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Re: Ye Old unknown-block(179,2)

Tue Sep 10, 2019 12:20 pm

Thanks for the commands procount, very helpful and great idea to get under the hood here and see what's happening.

As soon as I put the sdcard in the reader I got:
ErrorMounting.jpg
ErrorMounting.jpg (132.57 KiB) Viewed 254 times
.
I ran the fsck command and it found errors. I answered yes to fix a few, then fix all, then the screen started racing by with literally hundreds possibly thousands of errors! (btw, the errors weren't like it couldn't read the sdcard, they were more like this bit or that bit are in the wrong place etc.)

Surprisingly after it was done I was able to mount the volume, and it looked good with all the normal root directories you would see (home, etc.) Just for kicks I tried to boot off it, but new message:
resize_error.JPG
resize_error.JPG (29.81 KiB) Viewed 254 times
.
Wait is this an issue where somehow the file system resize command that is normally issued on first raspian boot isn't firing for some reason?

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procount
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Re: Ye Old unknown-block(179,2)

Tue Sep 10, 2019 12:26 pm

Well, it wouldn't have run before when you had the 179,2 error.
Now it's not running for another reason - maybe there are still some disk errors.

But you shouldn't have such errors at all since this is a fresh Raspbian install.
Maybe you should check the md5 checksum of the Raspbian image file you originally downloaded, or redownload it again.
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pcmanbob
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Re: Ye Old unknown-block(179,2)

Tue Sep 10, 2019 1:03 pm

procount wrote:
Tue Sep 10, 2019 12:26 pm

Maybe you should check the md5 checksum of the Raspbian image file you originally downloaded, or redownload it again.
I would normally agree with that statement , except in this case the OP has 4 SD cards the 2 SanDisk ones don't work, but the 2 Microcenter ones do work, assuming same image file used for both it rules out the image file being bad.

I wonder is the card reader used is not fully compatible with the SanDisk 32GB MicroSD HC Ultra Uhs-1 Memory Cards ?
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JeffZ123
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Re: Ye Old unknown-block(179,2)

Tue Sep 10, 2019 1:30 pm

You know what - that's a good point. It could be the card reader. I'm going to try a different device.

JeffZ123
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Re: Ye Old unknown-block(179,2)

Tue Sep 10, 2019 1:53 pm

Just to make sure I'm not crazy, I took a 32GB Microcenter card and repeated the process with the same exact image & hardware (down to the sd adapter.) and it worked. The first thing I see is "resizing the file system, rebooting in 5 seconds." then it boots into raspian no issues.

I'll try with a different SD card reader and report back.

JeffZ123
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Re: Ye Old unknown-block(179,2)

Tue Sep 10, 2019 2:46 pm

Ok - Mystery Solved!! It was the card reader causing the problem. I used a different PC with a built-in card reader and it worked no issues.

The Culprit :twisted:
s-l640.jpg
s-l640.jpg (27.39 KiB) Viewed 202 times
I was using one of those cheap "all in one" external card readers (pictured above) Never gave me problems before, but I guess something with it is not agreeable to the sandisk sd's.

Thanks guys for your help narrowing down this issue to the card reader!!

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procount
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Re: Ye Old unknown-block(179,2)

Tue Sep 10, 2019 2:54 pm

Probably more due to the fact that the Sandisk's are UHS-1 and your microcentre SDs and card reader are probably not.

Background info about the bewildering array of different SD card modes can be found at: https://en.wikipedia.org/wiki/SD_card#U ... peed_(UHS)
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JeffZ123
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Re: Ye Old unknown-block(179,2)

Tue Sep 10, 2019 3:09 pm

Hmm yes, good point. I googled a bit for a driver or firmware update for the dock to no avail. In fact I can't even tell who made it! Seems to be a generic unit model "875" from china.

I suppose I could take it apart and poke around at the chips :D but that's a project for another day.

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pcmanbob
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Re: Ye Old unknown-block(179,2)

Tue Sep 10, 2019 4:57 pm

Glad you finally solved your SD card problem.

With the ever changing SD card ranges and specifications I can see this becoming more of a problem as people don't tend to upgrade there card readers very often.
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