Ok,
given that I did not get any answer here (nor anywhere else) I tried writing an app that queries the Health Status Register through the the SD General Command (GEN_CMD) as described in the spec (CMD56 with argument of [00 00 00 01]).
Anyone tried this? Whatever I try to send as query to the SD (using Windows 10 call similar to:
<font face="terminal,monaco" size="2">DeviceIoControl(dev_hdl, IOCTL_SFFDISK_DEVICE_COMMAND, pCmd, nSizeofCmd, pCmd, nSizeofCmd, &dwBytesReturned, NULL);
</font>
I get error 0x32 (ERROR_NOT_SUPPORTED, i.e., guess: “The request is not supported.” 
)
I have read that you have to connect your SD card directly to the PCI bus because if it goes through a USB device, the USB driver intecepts the ioctl and complains … I hope this is not true, but I do not know the USB implementation on Windows (or on Linux for that matter …).
Any help much appreciated.
Marco
