Hi, For what it's worth, it seems on this specific hardware:
Broadcom Limited BCM57765/57785 SDXC/MMC Card Reader [14e4:16bc] the problem can be resolved by passing: debug_quirks2=0x4 to sdhci kernel module. Note that there is also the debug_quirks param. I did set some values for it but the working one is the default, namely 0 For more information have a look at https://bugzilla.kernel.org/show_bug.cgi?id=73241#c55 I just tested it on a Macmini7,1Debian having Stretch with 4.19+101~bpo9+1 kernel. I 'll be using it for the next few days, I am hoping everything will work out ok and I won't have to report more stuff