and here a KernelLog:
...
[ 390.430000] usb 1-1.1: USB disconnect, device number 18
[ 390.440000] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 390.440000] option 1-1.1:1.0: device disconnected
[ 390.450000] sd 15:0:0:0: [sdb] Synchronizing SCSI cache
[ 390.450000] sd 15:0:0:0: [sdb]
[ 390.450000] Result: hostbyte=0x01 driverbyte=0x00
[ 390.460000] option1 ttyUSB1: option_instat_callback: error -143
[ 390.460000] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 390.460000] option 1-1.1:1.2: device disconnected
[ 395.280000] usb 1-1.1: new high-speed USB device number 19 using ehci-platform
[ 395.420000] usb 1-1.1: New USB device found, idVendor=19d2, idProduct=2000
[ 395.420000] usb 1-1.1: New USB device strings: Mfr=2, Product=1, SerialNumber=3
[ 395.420000] usb 1-1.1: Product: ZTE CDMA Technologies MSM
[ 395.430000] usb 1-1.1: Manufacturer: ZTE,Incorporated
[ 395.430000] usb 1-1.1: SerialNumber: 3AUP673A4CDROMMS
[ 395.440000] scsi16 : usb-storage 1-1.1:1.0
[ 400.930000] usb 1-1.1: USB disconnect, device number 19
[ 406.290000] usb 1-1.1: new high-speed USB device number 20 using ehci-platform
[ 406.430000] usb 1-1.1: New USB device found, idVendor=19d2, idProduct=0064
[ 406.430000] usb 1-1.1: New USB device strings: Mfr=2, Product=1, SerialNumber=0
[ 406.430000] usb 1-1.1: Product: ZTE CDMA Technologies MSM
[ 406.430000] usb 1-1.1: Manufacturer: ZTE,Incorporated
[ 406.440000] option 1-1.1:1.0: GSM modem (1-port) converter detected
[ 406.440000] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB0
[ 406.450000] scsi17 : usb-storage 1-1.1:1.1
[ 406.450000] option 1-1.1:1.2: GSM modem (1-port) converter detected
[ 406.450000] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB1
[ 407.450000] scsi 17:0:0:0: Direct-Access ZTE MMC Storage 2.31 PQ: 0 ANSI: 2
[ 407.470000] sd 17:0:0:0: [sdb] Attached SCSI removable disk
[ 416.820000] hub 1-1:1.0: cannot reset port 4 (err = -71)
[ 416.820000] hub 1-1:1.0: cannot reset port 4 (err = -71)
[ 416.990000] option1 ttyUSB1: option_instat_callback: error -71
[ 417.060000] usb 1-1.1: USB disconnect, device number 20
[ 417.060000] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 417.060000] option 1-1.1:1.0: device disconnected
[ 417.070000] option1 ttyUSB1: option_instat_callback: error -143
[ 417.070000] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 417.080000] option 1-1.1:1.2: device disconnected
[ 417.100000] usb 1-1.4: reset high-speed USB device number 4 using ehci-platform
[ 417.210000] usb 1-1.4: device descriptor read/64, error -71
[ 418.720000] sd 1:0:0:0: [sda] No Caching mode page present
[ 418.720000] sd 1:0:0:0: [sda] Assuming drive cache: write through
[ 422.420000] usb 1-1.1: new high-speed USB device number 21 using ehci-platform
[ 422.560000] usb 1-1.1: New USB device found, idVendor=19d2, idProduct=2000
[ 422.560000] usb 1-1.1: New USB device strings: Mfr=2, Product=1, SerialNumber=3
[ 422.560000] usb 1-1.1: Product: ZTE CDMA Technologies MSM
[ 422.570000] usb 1-1.1: Manufacturer: ZTE,Incorporated
[ 422.570000] usb 1-1.1: SerialNumber: 3AUP673A4CDROMMS
[ 422.570000] scsi18 : usb-storage 1-1.1:1.0
[ 423.580000] scsi 18:0:0:0: CD-ROM ZTE USB SCSI CD-ROM 2.31 PQ: 0 ANSI: 2
[ 435.750000] usb 1-1.1: USB disconnect, device number 21
[ 440.340000] usb 1-1.1: new high-speed USB device number 22 using ehci-platform
[ 440.480000] usb 1-1.1: New USB device found, idVendor=19d2, idProduct=2000
[ 440.480000] usb 1-1.1: New USB device strings: Mfr=2, Product=1, SerialNumber=3
[ 440.480000] usb 1-1.1: Product: ZTE CDMA Technologies MSM
[ 440.490000] usb 1-1.1: Manufacturer: ZTE,Incorporated
[ 440.490000] usb 1-1.1: SerialNumber: 3AUP673A4CDROMMS
[ 440.500000] scsi19 : usb-storage 1-1.1:1.0
[ 445.990000] usb 1-1.1: USB disconnect, device number 22
[ 451.350000] usb 1-1.1: new high-speed USB device number 23 using ehci-platform
[ 451.490000] usb 1-1.1: New USB device found, idVendor=19d2, idProduct=0064
[ 451.490000] usb 1-1.1: New USB device strings: Mfr=2, Product=1, SerialNumber=0
[ 451.490000] usb 1-1.1: Product: ZTE CDMA Technologies MSM
[ 451.490000] usb 1-1.1: Manufacturer: ZTE,Incorporated
[ 451.500000] option 1-1.1:1.0: GSM modem (1-port) converter detected
[ 451.500000] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB0
[ 451.510000] scsi20 : usb-storage 1-1.1:1.1
[ 451.510000] option 1-1.1:1.2: GSM modem (1-port) converter detected
[ 451.510000] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB1
[ 452.510000] scsi 20:0:0:0: Direct-Access ZTE MMC Storage 2.31 PQ: 0 ANSI: 2
[ 452.530000] sd 20:0:0:0: [sdb] Attached SCSI removable disk