J'ai pu réparer le filesystem de mon Garmin Edge 1000 :

sudo fsck.msdos -artvV /dev/sdb
fsck.fat 4.1 (2017-01-24)
Checking we can access the last sector of the filesystem
0x41: Dirty bit is set. Fs was not properly unmounted and some data may be corrupt.
1) Remove dirty bit
2) No action
? 1
Boot sector contents:
System ID "mkdosfs"
Media byte 0xf8 (hard disk)
       512 bytes per logical sector
      4096 bytes per cluster
         8 reserved sectors
First FAT starts at byte 4096 (sector 8)
         1 FATs, 32 bit entries
   7593984 bytes per FAT (= 14832 sectors)
Root directory start at cluster 2 (arbitrary size)
Data area starts at byte 7598080 (sector 14840)
   1897593 data clusters (7772540928 bytes)
32 sectors/track, 64 heads
         0 hidden sectors
  15195586 sectors total
Starting check/repair pass.
Checking for bad clusters.
Reclaiming unconnected clusters.
Checking free cluster summary.
Starting verification pass.
Checking for unused clusters.
Perform changes ? (y/n) y
/dev/sdb: 188 files, 1798770/1897593 clusters

J'ai aussi dû changer de câble micro USB.