I might have been lucky. But then again, I did not test my duplicate cards, just the uniquely different ones, i.e., brands and sizes.I have all kinds of cards and tried all kinds of formats: Sandisk, Sony, Samsung, 16GB, 32GB, 64GB, 128GB, 256GB, UHS-I, UHS-II, Micro-SD, FAT32, exFAT, HFS+, and can discern no pattern of which work and which don't. Even two apparently identical cards behave differently. All work perfectly via a Dongle or in another (Intel) Mac. If I could figure for sure what type/brand/format of card works, I would know what to buy in the future.
Good to know, but not good to hear.No, not using HDMI. Thanks for the thought