My HW/SW design team is deep into the design cycle of a consumer device that has a micro SD card socket. We chose SPI communication instead of SDIO. The choice has mostly worked but we're starting to have regrets because a small percentage of SD cards we've seen will not function correctly when used with SPI. We have a handful of competing products that read the failing cards and have found that none of them use SPI. That gives me some doubt about our choice.
Has anybody out there been down this same path but instead chose SDIO over SPI because of SPI compatibility problems?
Thanks - John