[geekmaster]

Whoa! After going through a stack of microSDHC cards that all failed (0MB size in K1 settings menu), all of a sudden one I had not tested before showed up as 16MB). Cool!

They sure are fussy though (but the K1 mmc module makes a bunch of ASSUMPTIONS about SDHC, rather than trying to read its CID data to see what features it supports). Apparently those assumptions fail on most of my microSDHC cards.

I recall a similar problem a decade ago, when the linux mmc source code contained comments about the guesses it was making about cards, and attempting to access them at a bunch of clock speeds and such -- with web pages compiling lists of which makes and models of SD cards were "linux-compatible". And of course, these K1 drivers ARE a decade old, so really lucky they even WORK AT ALL on a card manufactured in recent years...

As it turns out, this microSDHC card is a 16GB class 2 SanDisk card. Perhaps that "class 2" is important, to prevent the K1 mmc driver from trying to talk to it too fast? Or maybe modern microSDHC cards refuse to operate slow enough for a K1? Perhaps the class (i.e. max write speed) is the important factor on K1 microSDHC compatibility, rather than storage capacity. If so, I need to start collecting (really slow but large capacity) "class 2" cards... I remember fighting this battle when my Palm Pilot (clone) had a max SD card capacity of 1GB, and the smallest the stores sold when I needed one was 2GB. It seems class 2 works (SD or SDHC), but class 4 does not -- and most of my microSD cards are class 10, and they definitely do not work.