а ты размонтируешь ли ее перед форматированием и монтируешь ли после, что дмесг пишет в момент попытки записи?
, SCSI device sda: 30842880 512-byte hdur sectors (15792 MB)
usb-uhci.c: interrupt, status 3, franela 678
sda: Write Protect is off
sda: unknown partition table
usb-uhci.c: interrupt, status 3, frane# 998
usb. c: USB discomect on device 88:01.2-1 address
2
Device not ready. Make sure there is a disc in the drive.
sda : READ CAPACITY failed.
sda : status = 1, nessage = 80, host8, driver = 08
Info fid-Oxa00 (nonstd), Current sd00:00: sense key Not Ready
sda : block size assumed to be 512 bytes, disk size 1GB.
sda: 1/0 error: dev 88:00, sector
error: deu 88:88, sector 2
error: de 08:00, sector
I/0 error: dev 08:00, sector 6
unable to read partition table
hub. c: new USB device 00:01.2-1, assigned address 3
WARNING: USB Mass Storage data integrity not assured
USB Mass Storage device found at
SCSI device sda: 30842886 512-byte hdur sectors (15792 MB)
usb-uhci.c: interrupt, status 3, frames 871
sda: Write Protect is off
sda: unknown partition table
EXT2-fs warning: mounting unchecked fs, running e2fsck is recommended
usb-uhci.c: interrupt, status 3, frames 2809