I have a setup with a micro SD card which may be suffering signal integrity issues. One suggested remedy is to try it with a slower card. I had some success with a 2GB Class 2 card from the dark ages, but 2GB is too small to test properly. There's nothing I can really change about the setup - it appears the speed selection is happening in ROM, so if I put in a fast card the faster speeds get enabled, and then fail.
So I'm looking for 8-32GB micro SD cards that don't support all the fancy modern speed grades. Most of the market is advertising how speedy they are. A scour of Amazon has found some class 4 cards. I have class 6 and class10 cards that don't work.
I had a look around industrial SD cards and they also make a big thing of speed.
So are there any SD cards that can somehow be programmed to only run the slowest speed modes, in a way that will persist over power cycle? Or a source of larger cards that only implement the older SD v2.0 spec?
I suppose one option would be a non-SDHC 4GB card, which just might be big enough with some trimming and probably use SD 2.0. But I don't know those were ever produced in the micro size.