TF cards v MicroSD

I think the name TF is a hack used by mainly Chinese sellers to avoid the SD Card Association trademarks.

Originally SD cards were intended to be used as a DRMed medium (hence the 'Secure' bit of the name) - the idea was you could buy songs on SD cards that you could play but not copy. I'm not sure if the DRM parts were present in the TF standard to begin with, but since it was adopted by the SD card association they have been for years. Nobody uses them today anyway.

So TF == microSD.

OP, what cards are you having problems with? Where did you buy them from? Any chances they are fakes?

Theo

Yup. seen all of that before.

and yet they don't work! At least for me. Has anyone ever booted a Pi (of any sort) using a TF card?

Both bought from, and returned to Amazon. and yes, of course, they could be fakes.

these :

No chance the exFAT format is the problem? I've never used more than 32 GB cards. The slow speed is implied in the spec.

I usually use SanDisk.

David

No. They get re-formatted to EXT4 during the imaging process.

I have 3 Pi using 64Gb cards without a problem. The rest use 8 or 32GB cards. I think they're currently all Sandisk although I have used some others (Lidl , Fuji , Samsung)

Cut from the ad -- ▲Fast Transfer Speed - The Micro SDXC card adopts Speed Class UHS-I(U1) and Class 10(C10) and provides you with 80MB/s of read speed and 15MB/s of write speed, and supports full HD video recording. (The Performance may vary based on host device, interface, usage conditions, and other factors.)

I usually use SanDisk too but had run out of the 64Gb cards. The 32Gb cards in use, in security cameras, are getting past 92% full on one of the cameras, hence me wanting a larger card.

There's no such thing as a TF card, aside from 20 year old ones. MicroSD and TF are one and the same.

So you got 2x512GB for £20? That sounds exceedingly dodgy. Currently a single Sandisk 512GB card is £40.

No idea about the 'Kootion' cards - but I'd stick to known brands, and avoid those shipped by marketplace sellers.

I'm not sure Raspi-imager will notice the card is fake. It'll write the

Theo

Thanks for the reply, Nev. I use H2testw for capacity checking. Amazon are good for refunds, but I hope someone else doesn't have the same issue -if they read the reviews!

Are you sure that’s 9Mb/s, rather than, say, 9MB/s?

Yup. My bad typing. 9MB/s

On 22 May 2024, Theo said the following... Th> I'm not sure Raspi-imager will notice the card is fake. It'll write the Th> 1-4GB image it has to the card, and if the card has let's say an 8GB real Th> capacity then everything will go fine and it'll verify correctly. But as Th> soon as you start using more of the card beyond the first 8GB - eg the Th> first time boot which resizes the partition to use the whole card - then Th> it'll start silently overwriting the OS.

There's a free utility for Windows that GRC published called ValiDrive that can help detect fake cards/usb sticks/drives, etc:

Jay

... Don't kiss an elephant on the lips today

you can test the card with "badblocks -o /report -t random -swv /dev/your_sd" and see the report. Then "cp /dev/zero /dev/your_sd" and ctrl+c after few seconds to make clean space for partition table.

I don't think that works - if I read the manual correct, badblocks writes the same pattern to all blocks, it will not detect fake cards where multiple blocks map to the same memory location.

You can use f3write / f3read. Those write files with known, non-repeating patterns to fill the whole device (you need a filesystem for that), and then verify them.

cu Michael

TIL: “f3” = “Fight Flash Fraud”.