Hi All, Here lsusb -v output: Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.00 bDeviceClass 9 Hub bDeviceSubClass 0 Unused bDeviceProtocol 0 Full speed (or root) hub bMaxPacketSize0 64 idVendor 0x1d6b Linux Foundation idProduct 0x0002 2.0 root hub bcdDevice 3.00 iManufacturer 3 Linux 3.0.0-13-generic ehci_hcd iProduct 2 EHCI Host Controller iSerial 1 0000:00:1d.7 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 25 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xe0 Self Powered Remote Wakeup MaxPower 0mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 1 bInterfaceClass 9 Hub bInterfaceSubClass 0 Unused bInterfaceProtocol 0 Full speed (or root) hub iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0004 1x 4 bytes bInterval 12 Hub Descriptor: bLength 9 bDescriptorType 41 nNbrPorts 6 wHubCharacteristic 0x000a No power switching (usb 1.0) Per-port overcurrent protection bPwrOn2PwrGood 10 * 2 milli seconds bHubContrCurrent 0 milli Ampere DeviceRemovable 0x00 PortPwrCtrlMask 0xff Hub Port Status: Port 1: 0000.0100 power Port 2: 0000.0100 power Port 3: 0000.0100 power Port 4: 0000.0100 power Port 5: 0000.0100 power Port 6: 0000.0100 power Device Status: 0x0003 Self Powered Remote Wakeup Enabled Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 9 Hub bDeviceSubClass 0 Unused bDeviceProtocol 0 Full speed (or root) hub bMaxPacketSize0 64 idVendor 0x1d6b Linux Foundation idProduct 0x0001 1.1 root hub bcdDevice 3.00 iManufacturer 3 Linux 3.0.0-13-generic uhci_hcd iProduct 2 UHCI Host Controller iSerial 1 0000:00:1d.0 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 25 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xe0 Self Powered Remote Wakeup MaxPower 0mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 1 bInterfaceClass 9 Hub bInterfaceSubClass 0 Unused bInterfaceProtocol 0 Full speed (or root) hub iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0002 1x 2 bytes bInterval 255 Hub Descriptor: bLength 9 bDescriptorType 41 nNbrPorts 2 wHubCharacteristic 0x000a No power switching (usb 1.0) Per-port overcurrent protection bPwrOn2PwrGood 1 * 2 milli seconds bHubContrCurrent 0 milli Ampere DeviceRemovable 0x00 PortPwrCtrlMask 0xff Hub Port Status: Port 1: 0000.0100 power Port 2: 0000.0100 power Device Status: 0x0003 Self Powered Remote Wakeup Enabled Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 9 Hub bDeviceSubClass 0 Unused bDeviceProtocol 0 Full speed (or root) hub bMaxPacketSize0 64 idVendor 0x1d6b Linux Foundation idProduct 0x0001 1.1 root hub bcdDevice 3.00 iManufacturer 3 Linux 3.0.0-13-generic uhci_hcd iProduct 2 UHCI Host Controller iSerial 1 0000:00:1d.1 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 25 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xe0 Self Powered Remote Wakeup MaxPower 0mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 1 bInterfaceClass 9 Hub bInterfaceSubClass 0 Unused bInterfaceProtocol 0 Full speed (or root) hub iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0002 1x 2 bytes bInterval 255 Hub Descriptor: bLength 9 bDescriptorType 41 nNbrPorts 2 wHubCharacteristic 0x000a No power switching (usb 1.0) Per-port overcurrent protection bPwrOn2PwrGood 1 * 2 milli seconds bHubContrCurrent 0 milli Ampere DeviceRemovable 0x00 PortPwrCtrlMask 0xff Hub Port Status: Port 1: 0000.0100 power Port 2: 0000.0100 power Device Status: 0x0003 Self Powered Remote Wakeup Enabled Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 9 Hub bDeviceSubClass 0 Unused bDeviceProtocol 0 Full speed (or root) hub bMaxPacketSize0 64 idVendor 0x1d6b Linux Foundation idProduct 0x0001 1.1 root hub bcdDevice 3.00 iManufacturer 3 Linux 3.0.0-13-generic uhci_hcd iProduct 2 UHCI Host Controller iSerial 1 0000:00:1d.2 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 25 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xe0 Self Powered Remote Wakeup MaxPower 0mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 1 bInterfaceClass 9 Hub bInterfaceSubClass 0 Unused bInterfaceProtocol 0 Full speed (or root) hub iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0002 1x 2 bytes bInterval 255 Hub Descriptor: bLength 9 bDescriptorType 41 nNbrPorts 2 wHubCharacteristic 0x000a No power switching (usb 1.0) Per-port overcurrent protection bPwrOn2PwrGood 1 * 2 milli seconds bHubContrCurrent 0 milli Ampere DeviceRemovable 0x00 PortPwrCtrlMask 0xff Hub Port Status: Port 1: 0000.0100 power Port 2: 0000.0103 power enable connect Device Status: 0x0003 Self Powered Remote Wakeup Enabled Bus 004 Device 002: ID 0cf2:6220 ENE Technology, Inc. SD Card Reader (SG361) Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.00 bDeviceClass 0 (Defined at Interface level) bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 64 idVendor 0x0cf2 ENE Technology, Inc. idProduct 0x6220 SD Card Reader (SG361) bcdDevice 1.00 iManufacturer 1 ENE iProduct 2 UB6220 iSerial 4 606569746801 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 32 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0x80 (Bus Powered) MaxPower 498mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 2 bInterfaceClass 8 Mass Storage bInterfaceSubClass 6 SCSI bInterfaceProtocol 80 Bulk (Zip) iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x01 EP 1 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x82 EP 2 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 0 Device Status: 0x0000 (Bus Powered) * * * Device works fine on OSwintXP and DSL Linux (2.4.31) 52 MB RAM I didn't find 2.4 kernel to build and test myself. After sticking the device's led is blinking and any operations (mount,fdisk,eject) will hang. dmesg outputs (on linux 2.6 and 3.0 same thing) * * * [ 101.868018] usb 1-6: new high speed USB device using ehci_hcd and address 2 [ 101.936241] hub 1-0:1.0: unable to enumerate USB device on port 6 [ 102.204027] usb 4-2: new full speed USB device using uhci_hcd and address 2 [ 102.543218] usbcore: registered new interface driver uas [ 102.583332] Initializing USB Mass Storage driver... [ 102.583535] scsi2 : usb-storage 4-2:1.0 [ 102.585561] usbcore: registered new interface driver usb-storage [ 102.585568] USB Mass Storage support registered. [ 103.596815] scsi 2:0:0:0: Direct-Access USB2.0 CardReader SD 0100 PQ: 0 ANSI: 0 [ 103.603436] sd 2:0:0:0: Attached scsi generic sg3 type 0 [ 103.695769] sd 2:0:0:0: [sdc] 994304 512-byte logical blocks: (509 MB/485 MiB) [ 103.698770] sd 2:0:0:0: [sdc] Write Protect is off [ 103.698778] sd 2:0:0:0: [sdc] Mode Sense: 03 00 00 00 [ 103.698782] sd 2:0:0:0: [sdc] Assuming drive cache: write through [ 103.711757] sd 2:0:0:0: [sdc] Assuming drive cache: write through [ 103.717889] sdc: sdc1 [ 103.727830] sd 2:0:0:0: [sdc] Assuming drive cache: write through [ 103.727841] sd 2:0:0:0: [sdc] Attached SCSI removable disk [ 283.802708] sd 2:0:0:0: timing out command, waited 180s [ 283.802729] sd 2:0:0:0: [sdc] Unhandled sense code [ 283.802733] sd 2:0:0:0: [sdc] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [ 283.802739] sd 2:0:0:0: [sdc] Sense Key : Hardware Error [current] [ 283.802746] sd 2:0:0:0: [sdc] Add. Sense: Unrecovered read error [ 283.802753] sd 2:0:0:0: [sdc] CDB: Read(10): 28 00 00 0f 2b f0 00 00 08 00 [ 283.802765] end_request: I/O error, dev sdc, sector 994288 [ 283.802773] Buffer I/O error on device sdc, logical block 124286 [ 463.818656] sd 2:0:0:0: timing out command, waited 180s [ 463.818673] sd 2:0:0:0: [sdc] Unhandled sense code [ 463.818677] sd 2:0:0:0: [sdc] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [ 463.818683] sd 2:0:0:0: [sdc] Sense Key : Hardware Error [current] [ 463.818690] sd 2:0:0:0: [sdc] Add. Sense: Unrecovered read error [ 463.818698] sd 2:0:0:0: [sdc] CDB: Read(10): 28 00 00 0f 2b f0 00 00 08 00 [ 463.818711] end_request: I/O error, dev sdc, sector 994288 [ 463.818719] Buffer I/O error on device sdc1, logical block 124030 [ 480.168080] INFO: task udisks-part-id:1945 blocked for more than 120 seconds. [ 480.168087] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 480.168092] udisks-part-id D 00000000 0 1945 518 0x00000004 [ 480.168100] c0081d9c 00000086 00000000 00000000 ffffffff 00000040 ca73e78c c183a8c0 [ 480.168109] 890837a7 00000050 ca73e788 c183a8c0 c183a8c0 de8068c0 ca73e500 c1731f60 [ 480.168117] 00000246 c1784140 c1784140 00000001 c0081d90 00000246 de25e150 cd208060 [ 480.168126] Call Trace: [ 480.168141] [<c1272d12>] ? kobject_get+0x12/0x20 [ 480.168149] [<c1263888>] ? get_disk+0x48/0xa0 [ 480.168159] [<c1509096>] __mutex_lock_slowpath+0xd6/0x140 [ 480.168164] [<c1508c05>] mutex_lock+0x25/0x40 [ 480.168171] [<c1154e87>] __blkdev_get+0x47/0x360 [ 480.168176] [<c11551e9>] blkdev_get+0x49/0x250 [ 480.168181] [<c11547ae>] ? bd_acquire+0x3e/0xd0 [ 480.168185] [<c1155448>] blkdev_open+0x58/0x70 [ 480.168191] [<c11253c1>] __dentry_open+0xc1/0x280 [ 480.168196] [<c112672e>] nameidata_to_filp+0x6e/0x80 [ 480.168201] [<c11553f0>] ? blkdev_open+0x0/0x70 [ 480.168207] [<c1133bdf>] finish_open+0xaf/0x1a0 [ 480.168211] [<c1133488>] ? do_path_lookup+0x68/0x120 [ 480.168217] [<c1134227>] do_filp_open+0x207/0x6e0 [ 480.168223] [<c1126796>] do_sys_open+0x56/0x120 [ 480.168231] [<c13222d0>] ? write_null+0x0/0x10 [ 480.168236] [<c112688e>] sys_open+0x2e/0x40 [ 480.168241] [<c150a4a4>] syscall_call+0x7/0xb [ 600.168074] INFO: task udisks-daemon:1597 blocked for more than 120 seconds. [ 600.168081] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 600.168085] udisks-daemon D fe1248b5 0 1597 1 0x00000000 [ 600.168093] ca401ca4 00000086 0000006b fe1248b5 0000006b d8e01f16 cd3d9bcc c183a8c0 [ 600.168102] fe126839 0000006b cd3d9bc8 c183a8c0 c183a8c0 de8068c0 cd3d9940 d0eb25e0 [ 600.168110] de806920 de806904 d0eb260c d0eb260c ca401c9c 003d0f91 d90a9ef1 cd3d996c [ 600.168119] Call Trace: [ 600.168137] [<c15088dd>] schedule_timeout+0x1ed/0x260 [ 600.168144] [<c150a07d>] ? _raw_spin_lock+0xd/0x10 [ 600.168152] [<c103de37>] ? task_rq_lock+0x47/0x80 [ 600.168158] [<c1049f53>] ? try_to_wake_up+0x223/0x3c0 [ 600.168164] [<c1508460>] wait_for_common+0xa0/0x130 [ 600.168169] [<c104a124>] ? wake_up_process+0x14/0x20 [ 600.168173] [<c104a0f0>] ? default_wake_function+0x0/0x20 [ 600.168179] [<c15085c7>] wait_for_completion+0x17/0x20 [ 600.168186] [<c1068100>] flush_work+0x30/0x40 [ 600.168192] [<c10666d0>] ? wq_barrier_func+0x0/0x20 [ 600.168197] [<c10697eb>] flush_delayed_work+0x3b/0x40 [ 600.168203] [<c12650a5>] disk_clear_events+0x75/0x120 [ 600.168210] [<c1153c0d>] check_disk_change+0x2d/0x70 [ 600.168218] [<c1362d80>] sd_open+0xa0/0x1d0 [ 600.168224] [<c1272cad>] ? kobject_put+0x1d/0x50 [ 600.168230] [<c1155162>] __blkdev_get+0x322/0x360 [ 600.168236] [<c11551e9>] blkdev_get+0x49/0x250 [ 600.168240] [<c11547ae>] ? bd_acquire+0x3e/0xd0 [ 600.168245] [<c1155448>] blkdev_open+0x58/0x70 [ 600.168251] [<c11253c1>] __dentry_open+0xc1/0x280 [ 600.168256] [<c112672e>] nameidata_to_filp+0x6e/0x80 [ 600.168260] [<c11553f0>] ? blkdev_open+0x0/0x70 [ 600.168266] [<c1133bdf>] finish_open+0xaf/0x1a0 [ 600.168271] [<c1133488>] ? do_path_lookup+0x68/0x120 [ 600.168276] [<c1134227>] do_filp_open+0x207/0x6e0 [ 600.168284] [<c113ff79>] ? vfsmount_lock_local_unlock+0x19/0x20 [ 600.168290] [<c1126796>] do_sys_open+0x56/0x120 [ 600.168295] [<c112859d>] ? fput+0x1d/0x30 [ 600.168299] [<c112688e>] sys_open+0x2e/0x40 [ 600.168305] [<c150a4a4>] syscall_call+0x7/0xb [ 600.168317] INFO: task udisks-part-id:1945 blocked for more than 120 seconds. [ 600.168320] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 600.168324] udisks-part-id D 00000000 0 1945 518 0x00000004 [ 600.168330] c0081d9c 00000086 00000000 00000000 ffffffff 00000040 ca73e78c c183a8c0 [ 600.168338] 890837a7 00000050 ca73e788 c183a8c0 c183a8c0 de8068c0 ca73e500 c1731f60 [ 600.168347] 00000246 c1784140 c1784140 00000001 c0081d90 00000246 de25e150 cd208060 [ 600.168355] Call Trace: [ 600.168361] [<c1272d12>] ? kobject_get+0x12/0x20 [ 600.168368] [<c1263888>] ? get_disk+0x48/0xa0 [ 600.168374] [<c1509096>] __mutex_lock_slowpath+0xd6/0x140 [ 600.168380] [<c1508c05>] mutex_lock+0x25/0x40 [ 600.168385] [<c1154e87>] __blkdev_get+0x47/0x360 [ 600.168390] [<c11551e9>] blkdev_get+0x49/0x250 [ 600.168395] [<c11547ae>] ? bd_acquire+0x3e/0xd0 [ 600.168400] [<c1155448>] blkdev_open+0x58/0x70 [ 600.168404] [<c11253c1>] __dentry_open+0xc1/0x280 [ 600.168409] [<c112672e>] nameidata_to_filp+0x6e/0x80 [ 600.168414] [<c11553f0>] ? blkdev_open+0x0/0x70 [ 600.168419] [<c1133bdf>] finish_open+0xaf/0x1a0 [ 600.168424] [<c1133488>] ? do_path_lookup+0x68/0x120 [ 600.168429] [<c1134227>] do_filp_open+0x207/0x6e0 [ 600.168435] [<c1126796>] do_sys_open+0x56/0x120 [ 600.168442] [<c13222d0>] ? write_null+0x0/0x10 [ 600.168447] [<c112688e>] sys_open+0x2e/0x40 [ 600.168452] [<c150a4a4>] syscall_call+0x7/0xb [ 643.826626] sd 2:0:0:0: timing out command, waited 180s [ 643.826645] sd 2:0:0:0: [sdc] Unhandled sense code [ 643.826649] sd 2:0:0:0: [sdc] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [ 643.826655] sd 2:0:0:0: [sdc] Sense Key : Hardware Error [current] [ 643.826662] sd 2:0:0:0: [sdc] Add. Sense: Unrecovered read error [ 643.826669] sd 2:0:0:0: [sdc] CDB: Read(10): 28 00 00 0f 2b f0 00 00 08 00 [ 643.826682] end_request: I/O error, dev sdc, sector 994288 [ 643.826690] Buffer I/O error on device sdc1, logical block 124030 Cheers, Jalil