I have a USB eMMC reader, vendor 0x05e3 product 0x0727, that does not work with FreeBSD because the kernel thinks the medium is not present. There is in fact a 16 GB card plugged in and the same reader+card combination works on a Mac. I tried copying some of the quirks for other vendor 05e3 devices with no luck. If there is a specific combination of quirks that should work I will try. This reader is sold by Pine64 as a companion for their ARM and RISC-V single board computers with eMMC connector. In the kernel output below there is a delay of five seconds between "Attached to scbus8" and "da0 at umass-sim0 bus 0 scbus8". umass0 on uhub4 umass0: <Generic USB Storage, class 0/0, rev 2.00/2.50, addr 3> on usbus7 umass0: SCSI over Bulk-Only; quirks = 0xc101 umass0:8:0: Attached to scbus8 da0 at umass-sim0 bus 0 scbus8 target 0 lun 0 da0: <Generic STORAGE DEVICE 0250> Removable Direct Access SCSI device da0: Serial Number 000000000250 da0: 40.000MB/s transfers da0: Attempt to query device size failed: NOT READY, Medium not present da0: quirks=0x3<NO_SYNC_CACHE,NO_6_BYTE> # usbconfig -d ugen7.2 dump_stats ugen7.2: <microSD Reader/Writer Genesys Logic, Inc.> at usbus7, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=ON (500mA) { UE_CONTROL_OK : 364 UE_ISOCHRONOUS_OK : 0 UE_BULK_OK : 1515 UE_INTERRUPT_OK : 0 UE_CONTROL_FAIL : 0 UE_ISOCHRONOUS_FAIL : 0 UE_BULK_FAIL : 648 UE_INTERRUPT_FAIL : 0 } # camcontrol inq pass4 pass4: <Generic STORAGE DEVICE 0250> Removable Direct Access SCSI device pass4: Serial Number 000000000250 pass4: 40.000MB/s transfers