Micro-SD card readers

I have just jiggered my Rpi3B+ trying to update in situ from RO5.27 to RO5.28. I now have 5 micro-SD cards (2 16GB, 2 64GB, 1 128GB) which, inserted into my USB card-reader, register nothing at all to my Raspbian computer. Can card-readers cease to function, or is it that Raspbian cannot read their format? The 128GB card was used in a mobile phone, and the others have all had RISC OS or Raspbian on them. I am expecting a batch of 8GB cards together with a card-reader in the post any time soon, which I hope to use for installing RISC OS 5.28 using the Imager program in Raspbian, as per the instructions on this site. But is any preparatory formatting required, or does Imager do all that? Or maybe there are Linux commands to read what is stuck into the USB sockets? Are micro-SD cards rescuable at all, or should I bin them?

Can card-readers cease to function

Yes, card readers can stop working (I’ve only ever had it happen once, to a card reader I’d bought in Poundland which had cost me £1, so not that expensive a mistake).

Try plugging in the card reader without a card inserted. If a drive appears on the icon bar, the card reader is probably OK (but may have dirty contacts or some other hardware issue). If nothing happens, the card reader may have failed.

But is any preparatory formatting required, or does Imager do all that?

Raspberry Pi Imager does everything for you. It should work just as well with an unformatted card.

Just an outside chance: your card reader does support SDHC cards? Very old ones only supported SD.

It would have to be very old for that to be your problem.

Try plugging in the card reader without a card inserted. If a drive appears on the icon bar, the card reader is probably OK (but may have dirty contacts or some other hardware issue). If nothing happens, the card reader may have failed.

I’ve had a couple of card readers that wouldn’t report themselves unless there was a card plugged in, so no card, no icon!

so no card, no icon!

Conversely there are some multi-format card readers that get reported as a device for every possible slot. So plug it in and there’s a E drive, an F drive, a G drive, and an H drive ¹. It’s a bit hit-and-miss as to which one actually represents the media inserted.

It would have to be very old for that to be your problem.

I wouldn’t put it past some unscrupulous places to flog them off cheap, failing to mention that “SD” is both a generic name and the name for cards of 2GB or less, and that larger cards are actually called “SDHC” or “SDXC”.
[and some devices, not wishing to use the SD name or logo, refer to them as “TF” cards (same as µSD), you’ll need to consult the device documents to see where they max out, but it’s usually one of 8, 16, or 32GB]

Yes, card readers can stop working

Quite frequently, actually. What tends to bugger up mine is recording from the satellite receiver or the PVR, as if several hours of non-stop writes somehow wears the thing out, which is rather ironic given that it’s the flash media that should be wearing out!

Some just cease working. Others trash the filesystem on the way out.

I’ve just bought myself a Transcend RDF5 for SD/µSD. I have enough cards that not having a reader handy would be a pain in the proverbial.

¹ Used under Windows, not RISC OS. I’d expect it to behave in a similar manner, though.

Are micro-SD cards rescuable at all, or should I bin them?

I have found that cards that don’t work in one reader will work in another. Also, that cards that are unreadable in one reader are “rescued” by using them in another, making them readable again in the first. It’s possible that some readers will issue vendor-specific commands to the cards.

Try plugging in the card reader without a card inserted. If a drive appears on the icon bar, the card reader is probably OK (but may have dirty contacts or some other hardware issue). If nothing happens, the card reader may have failed.

I think mine has failed. Thanks for this info. I am expecting a new card reader in the post next week, so I will wait for that before getting back to RISC OS.

I think mine has failed.

I have just looked again at the 32GB card I had put aside as catastrophically failed, run it by various readers, and have apparently reformatted it Filecore, created a new “FAT partition”, and remade it as a RISC OS bootable disc.

So I would recommend throwing nothing away. Start a reserve collection to revisit from time-to-time!

David’s advice was sound, apparently!