DragonFlyBSD

When I was trying to create a DragonFly Live-USBstick using
dd if=/usr/release/dfly.img of=/dev/da0 bs=1m
It kept on failing with errors several times but got "unstuck" when I
pulled out the USB stick. Finally dd worked, but only after 5 tries.

Errors were of the following sort with many repeated messages:

umass0: <USB DISK 2.0, class 0/0, rev 2.00/4.11, addr 2> on uhub0
da0 at umass-sim0 bus 0 target 0 lun 0
da0: <USB DISK 2.0 0411> Removable Direct Access SCSI-0 device
da0: 1.000MB/s transfers
da0: 968MB (1982464 512 byte sectors: 64H 32S/T 968C)
vn0s1: cannot find label (no disk label)
contigmalloc_map: failed in index < 0 case!
umass0: BBB reset failed, TIMEOUT
umass0: BBB bulk-in clear stall failed, TIMEOUT
umass0: BBB bulk-out clear stall failed, TIMEOUT

(da0:umass-sim0:0:0:0): Synchronize cache failed, status 0x4, scsi
status 0x0
(da0:umass-sim0:0:0:0): lost device
(da0:umass-sim0:0:0:0): removing device entry
camq: devq send_queue still in use
camq: devq alloc_queue still in use
camq: devq send_queue still in use
camq: devq alloc_queue still in use
camq: devq send_queue still in use

umass0: detached
umass0: <USBest Technology USB Mass Storage Device, class 0/0, rev
2.00/1.00, addr 2> on uhub0
da0 at umass-sim0 bus 0 target 0 lun 0
da0: <USB.NU USB2FlashStorage 0.00> Removable Direct Access SCSI-2 device
da0: 1.000MB/s transfers
da0: 1928MB (3948544 512 byte sectors: 255H 63S/T 245C)
contigmalloc_map: failed in index < 0 case!
contigmalloc_map: failed in index < 0 case!
contigmalloc_map: failed in index < 0 case!
contigmalloc_map: failed in index < 0 case!
contigmalloc_map: failed in index < 0 case!

and more and more... until it just worked!