I wasn't even surprised, when I plugged-in an SSD via USB 3.0 into Raspberry Pi 4 and it didn't work at all. That became a killer for my idea of keeping data outside of the Pi's microSD card. Observed suspicious symptoms were too obvious:
booting time increased from 20 seconds to 3 minutes LED light of the drive was constantly blinking some commands took extremely long time to execute (sudo blkid, sudo fdisk -l) and even later mounting finished failing or partition formatting hanged indefinitely.
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