Status of SD card compatibility - What should I buy?

[nicholfd]

I am ready to buy a few SD cards (thinking 8GB) for my ordered RaspberryPi.

I have read several posts/discussions regarding SD card compatibility.  From ALL of the information, it is not clear exactly what is working and what is not.  There was one post (I believe from Liz) to refer to the WiKi that there would be a SD compatibility chart - I can find no compatibility chart on the WiKi.

I want to buy Class 10 cards (I can't bring myself to by old, slow hardware... ;^) ), but have seen posts that suggests (doesn't confirm) these are not compatible.  Other posts are unclear.

Any pointers to solid information would be much appreciated.

Thanks.

[wolfje]

Looking at the wiki with verified cards, there are some class 10s in the list:

Wiki

Please have a look at that page, it also list the cards that give problems, but remember not every card is on the list or has been tested.

[rmm200]

Especially don't make the mistake of thinking Class 10 cards are "better" than Class 6 or Class 4. It depends on the application.

Typically Class 10 cards are great for huge data records read/written serially - like a video camera. Not the way the Pi uses memory at all.

[selsinork]

nicholfd said:


I am ready to buy a few SD cards (thinking 8GB) for my ordered RaspberryPi.

[...]

Any pointers to solid information would be much appreciated.



Added some more to the wiki, images of the cards here

I can confirm the ones I have do work in a real Raspberry Pi.

[nicholfd]

Thanks all, for the quick reply's.  I did look for the list on the WiKi before initially posting - I do not know why I couldn't find it, until wolfje pointed me straight to it.

Even though a class 10 card may not be faster for the RaspberryPi, should a class 10 card work, in general?  I saw some posts somewhere that stated that class 10 cards will not work in general, due to some voltage/design issue.

I ask about class 10 cards because I tend to buy and sometimes re-purpose items.  If I'm going to by SD cards, I would want to purchase ones that would have the most use later, if they are re-purposed.

Thanks again!

[rmm200]

Class 10 cards would not work without a kernel change to inhibit switching to a high speed mode the Pi can not support. I suspect that change may be in the latest Debian squeeze - but wait for verification from a current Pi owner.

[Chris.Rowland]

I had a look at the Git repository and from what I can see the change was made about a month ago and is in the current Debian distribution.

I don't have a Pi so can't do any tests for myself, but people seem to be reporting that class 10 cards are OK.

[dscott]

I initially installed the 13-04-2012 image of Debian for my Pi on an old Sandisk Extreme III 2GB SD card I had spare (code BE0715105083B), and this worked fine for initial testing.

However, I wanted more storage so scanned the forum for recommendations of larger capacity cards which worked (after reading about problems with most class 10 cards). I like Sandisk cards so when I saw a user reporting success with a Sandisk Ultra class 6 16GB card and found them online at a good price, I ordered a couple (code BL1202021933G)...

...only to experience the dreaded "mmc0 timeout waiting for interrupt" when I tried booting Debian from them

I also tried the Arch Linux distro at the same time and this didn't even attempt to boot.

After reading the post above about the new 19-04-2012 Debian image and the kernel patch I thought I'd give the new image a go on these cards.

Unfortunately it doesn't appear to have made any difference. I still get the same "mmc0 timeout..." issue on booting.

Has anyone else had success booting from an SD card with this latest image that they were previously unable to boot from?

Is there a definitive statement on this issue? Is it easily fixable? Is there an ETA for a fix?

[Chris.Rowland]

My guess is that your problem with a class 6 card is different.

The fix was for class 10 cards. Apparently they have to have their power supply changed to run at the higher speed.  The kernel was detecting that it was a high speed card and switching to the higher speed but the hardware didn't have the power supply switch implemented so it didn't run at the high speed.

The fix is to ignore the high speed detection and run the card at the lower speed.

I must stress that I've no official knowledge about this. All I've done is read the forums and look at the sources.

[dscott]

Thanks Chris. I had (probably mistakenly) assumed that the problem with my class 6 cards would be the same as that affecting class 10 cards.

I've actually got a spare class 10 card (Sandisk Extreme HD Video 8GB, code BI1108716254G) so let me try that now and report back...

[dscott]

OK - so I've now tried the class 10 card referenced earlier and my Pi will not boot.

The red light comes on but there's no further activity and nothing on the display.

So, even with the 19-04-2012 Debian image I can't boot from any of my Sandisk class 6 and class 10 cards.

I'd be very interested to hear if anyone who was having problems booting with earlier images is now able to boot with this latest 19-04-2012 image.

[rmm200]

There was also the comment - on the Wiki I think - that micro SD cards in an adapter would not work. I would welcome someone's comments here that they have tried micro SD cards and that they work.

[RaTTuS]

rmm200 said:


There was also the comment - on the Wiki I think - that micro SD cards in an adapter would not work. I would welcome someone's comments here that they have tried micro SD cards and that they work.


I have seen it mentioned that MicroSD + adapter has been shown to be working  btu I don't have the reference

[selsinork]

RaTTuS said:


I have seen it mentioned that MicroSD + adapter has been shown to be working  btu I don't have the reference


This microSD card + adapter works with Arch:





Some googling suggests that the MMBxxxxx marking on the back means it's actually made by Samsung, but I have no way to prove that.

There's some more images of cards I've proven to be working in a Pi here http://selsinork.imgur.com/  I've added them all to the wiki and will continue to do so as I'm able to test more.

I have some 8Gb class 10 cards ordered, including one UHS capable one, they should be here in a couple of days and I'll post another msg with results.

The comment about microSD cards not working seems to be something to do with Fedora, but I can't find the original mention of it.

Unfortunately it's now been parroted so often that it's taken on a life of it's own and become an absolutely irrefutable urban myth

[dscott]

selsinork - there's a typo in your SD card images link... looks like a superfluous trailing space

[rmm200]

The legend about micro sd cards comes from our friends at Seneca, and is still on their Fedora Remix page:

http://zenit.senecac.on.ca/wik.....stallation

Would be good if they could update that page.

[selsinork]

dscott said:


selsinork - there's a typo in your SD card images link... looks like a superfluous trailing space



Hmm.. and there was me thinking that cut&pasting it would work ok, right lets see if this works..

http://selsinork.imgur.com

[dscott]

I think it's fair to say there's still a lot of confusion around which cards work and which don't (for me, at least).

I specifically bought cards because someone else in the forum reported that they worked for them - but they don't work for me

And I see very similar Sandisk Ultra cards (same class and speed) as mine but in different sizes reported as working in the Wiki!

I've been using WinDiskImager32 and a USB SD card reader on a Windows PC so far to write images... could this be a contributing factor? I have Mac and Linux machines too - is it worth trying writing images to these problem cards from those other machines?

[selsinork]

rmm200 said:


The legend about micro sd cards comes from our friends at Seneca, and is still on their Fedora Remix page:


Ok, I'm downloading the fedora image right now, so will try it and see.

Ordinarily I'm not a fan of Fedora and after reading that there were some issues I'd never actually bothered trying it.

[selsinork]

selsinork said:

Ok, I'm downloading the fedora image right now, so will try it and see.
So, I can confirm that with the Peak 4Gb microSD card in the images earlier in this thread, in an adapter, the raspberrypi-fedora-remix-14-r1.img.gz I just downloaded works.

At least for some version of 'works', it's making me change my password on every login and there's some odd looking messages in dmesg:

[  388.664820] DEBUG:timer_callback:: Timer hc timer callback
[  388.675597] WARN::hc_xfer_timeout:1740: hc_xfer_timeout: timeout on channel 3
[  388.675611]
[  388.694734] WARN::hc_xfer_timeout:1742:      start_hcchar_val 0x00d88a00
[  388.694747]
[  403.392703] DEBUG:timer_callback:: Timer hc timer callback

however google suggests that's likely to be something to do with usb rather than the SD card...

CONFIG_USB_DEBUG=y

CONFIG_USB_SUSPEND=y

probably explains it..

So while I ultimately can't comment on any other microSD cards, the one I have works just fine with the fedora-remix.

I reserve judgment on fedora itself - don't think it'll be on there for very long.

[rmm200]

Having to change your password on every boot is "normal" on Fedora if you do not have an internet connection to get the current time from.  There have been a number of work-arounds posted.

[selsinork]

dscott said:


I think it's fair to say there's still a lot of confusion around which cards work and which don't (for me, at least).


confusion for all I think..


I specifically bought cards because someone else in the forum reported that they worked for them - but they don't work for me

And I see very similar Sandisk Ultra cards (same class and speed) as mine but in different sizes reported as working in the Wiki!


The feeling I get is that most of the sd cards are probably bought on the open market and simply badged with a sticky label with whatever name.

For example, I have a Sandisk and a transcend that apart from the label and black vs blue plastics are virtually indistinguishable - they even report the same controller and firmware versions.


is it worth trying writing images to these problem cards from those other machines?


Nothing to lose, so you might as well try..

pm me if you like and I'll send you details of where I bought the cards I've found to work.

[selsinork]

rmm200 said:


Having to change your password on every boot is "normal" on Fedora if you do not have an internet connection to get the current time from.  There have been a number of work-arounds posted.


Sorry, that counts as a bug in my book. Not going to work on a model A after all

While I realise it's still early days and there's bugs to be worked out, I find it a bit presumptuous to expect an internet connection.

That's not directly a criticism of fedora - it annoys me just as much when my blu-ray takes an extra few minutes hunting for some 'movie-extras' nonesense over a presumed always present internet connection too..

[rmm200]

The problem will be long gone by model A time. This is just a birthing bug.

[nicholfd]

All of this discussion is exactly why I started this tread.  There still doesn't seem to be good, clear information on what does really work or what to buy, if you want to make sure the SD card works with a Raspberry Pi.

An SD card is not just an SD card...

It seems that Class 4, full size SD cards are what most people are having the best luck with.  Anything rated at above Class 4 still seems to be failing (anyone seen confirmed reports that Class 6 works?)

MicroSD has been confirmed to work, in at least one case.

Is this a good summary?

Thanks.