piCore 7.0 mmc timeouts on armv6 pi with Samsung 8GB class 6 card

[fanoush]

Hi, I copied image to new Samsung 8GB class 6 card and it works fine in PI2 but it doesn't finish booting in any of my armv6 based PIs (a+,b+,Bv2-512MB,Bv1-256MB,Zero). It prints the piCore 7.0 banner and message about skipping rtc but then the card activity stays on and it hangs for many minutes. Sometimes it spits out some paging faults. Once, after many page faults, it gave me the shell and when seeing kernel log via dmesg I can cee many mmc card timeouts and resets and i/o errors in the log.

The same card boots fine in Pi2B.
When rewriting the same card with latest raspbian jessie image it boots without any issue in all mi PIs.
I tried to add dtoverlay=sdhost or dtoverlay=mmc to config.txt as decribed here
https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=129203 but it didn't make any difference.

[Greg Erskine]

hi fanoush,

piCore 7.0 has always worked on the different types of Raspberry Pi's for me.

Start a fresh, I think something must be missing or corrupt on your SD card.

regards
Greg

[fanoush]

Hi Greg, the card is not corrupted, tried more times. And when I put this 'corrupted' card into PI2 it works just fine and piCore boots to shell very quickly. I guess it is combination of this specific card model and the version of sd/mmc driver in linux kernel of piCore 7.0. Is there an easy way how to make piCore compatible kernel/initrd from the exact kernel binary that is used in raspbian jessie and works fine with this card?

[Paul_123]

Hi Greg, the card is not corrupted, tried more times. And when I put this 'corrupted' card into PI2 it works just fine and piCore boots to shell very quickly. I guess it is combination of this specific card model and the version of sd/mmc driver in linux kernel of piCore 7.0. Is there an easy way how to make piCore compatible kernel/initrd from the exact kernel binary that is used in raspbian jessie and works fine with this card?

It is the same Firmware and kernel, with a couple added different options.   On the older pi hardware, SD card problems is typically caused by inadequate power supplies. 

I've used at least 10 different brand cards with no problems.

[andyj]

I have a pile of Sandisk class 4 cards and they've all worked fine when I use a decent power supply. I've run into a bunch of power supplies that claimed to be 1.5A that couldn't power a Pi and as it turned out couldn't charge a cell phone either. Pretty much all the boot problems I've encountered have been power supply problems.

[patrikg]

Yes lots of power problems, take all usb stuff away, and try again.
Just ethernet and hdmi or composite.

[fanoush]

It is not power, I am using this same power adapter for years with my pis. Also it boots fine with PI2B in exactly same setup and does not boot with b+ or a+ which has lower power draw. And again when dd-ing the same card with jessie and putting it back it works just fine. In all cases I used only hdmi and usb keyboard with or without ethernet attached, no mouse or wi-fi dongle or anything else.

But thanks for trying to help. I will try again, possibly with sandisk 8gb class 4, I guess that one will work.

As for kernel version - until you use exactly the same stable version as jessie any minor version can make big difference see e.g. this thread https://www.raspberrypi.org/forums/viewtopic.php?f=66&t=60286&start=50 The latest from their github is not the most stable one.

And when checking the posts now, here is another person with same card https://www.raspberrypi.org/forums/viewtopic.php?p=895722#p895722 so that explains it :-(

[jgrulich]

The issue is a question of firmware. Update the latest firmware from git, than it will work.

[beerstein]

Hi: I just came across an interesting article in a computer magazine. The author stated that the speed class on SD and uSD cards was made for use in digital cameras and video cameras. Writing and reading (sequel) in computers should not be affected by the class. (At least not noticeable) I am not an expert but this could mean that we should not worry to much about having class 6 or class 10. Or?

[bmarkus]

Hi: I just came across an interesting article in a computer magazine. The author stated that the speed class on SD and uSD cards was made for use in digital cameras and video cameras. Writing and reading (sequel) in computers should not be affected by the class. (At least not noticeable) I am not an expert but this could mean that we should not worry to much about having class 6 or class 10. Or?

Depends on. If your application is working with large files and/or using lotof swap on the SD card e..g. when compiling Qt you see the performance difference. In other case when apps are running from RAM not really.

[fanoush]

just FYI, as expected when trying sandisk 8gb microsd card instead of samsung one everything works fine so it is indeed samsung card vs linux kernel version used in piCore 7