Tried again using unetbootin with the same result

This time I formatted the usb key as EXT4 and now I see some errors reported in dmesg:

[10957.453528] usb-storage 3-1:1.0: USB Mass Storage device detected
[10957.453697] scsi8 : usb-storage 3-1:1.0
[10958.454327] scsi 8:0:0:0: Direct-Access     TDK LoR  TF10             PMAP PQ: 0 ANSI: 6
[10958.454732] sd 8:0:0:0: Attached scsi generic sg2 type 0
[10960.199639] sd 8:0:0:0: [sdc] 15108480 512-byte logical blocks: (7.73 GB/7.20 GiB)
[10960.199846] sd 8:0:0:0: [sdc] Write Protect is off
[10960.199848] sd 8:0:0:0: [sdc] Mode Sense: 23 00 00 00
[10960.200052] sd 8:0:0:0: [sdc] No Caching mode page found
[10960.200054] sd 8:0:0:0: [sdc] Assuming drive cache: write through                                                                               
[10960.205263]  sdc: sdc1
[10960.206887] sd 8:0:0:0: [sdc] Attached SCSI removable disk
[10967.401204] EXT4-fs (sdc1): mounted filesystem with ordered data mode. Opts: (null)
[11172.459350] INFO: task extlinux:8675 blocked for more than 120 seconds.
[11172.459353]       Not tainted 3.16.0-30-generic #40-Ubuntu
[11172.459354] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[11172.459356] extlinux        D ffff88082fa13840     0  8675   8674 0x00000000
[11172.459359]  ffff8807d3117d70 0000000000000082 ffff880743fe1e90 0000000000013840
[11172.459361]  ffff8807d3117fd8 0000000000013840 ffff880743fe1e90 ffff8807d3117e98
[11172.459363]  ffff8807d3117e90 7fffffffffffffff ffff880743fe1e90 ffff880743fc2868
[11172.459366] Call Trace:
[11172.459372]  [<ffffffff81785509>] schedule+0x29/0x70
[11172.459374]  [<ffffffff817847c9>] schedule_timeout+0x229/0x2a0
[11172.459377]  [<ffffffff8108b256>] ? __queue_work+0x136/0x340
[11172.459379]  [<ffffffff8108b52a>] ? __queue_delayed_work+0xaa/0x1c0
[11172.459382]  [<ffffffff81786694>] wait_for_completion+0xb4/0x1e0
[11172.459386]  [<ffffffff810a5670>] ? wake_up_state+0x20/0x20
[11172.459391]  [<ffffffff81211ed0>] ? vfs_fsync+0x40/0x40
[11172.459394]  [<ffffffff8120b355>] sync_inodes_sb+0xa5/0x1c0
[11172.459396]  [<ffffffff81211ed0>] ? vfs_fsync+0x40/0x40
[11172.459399]  [<ffffffff81211ee9>] sync_inodes_one_sb+0x19/0x20
[11172.459402]  [<ffffffff811e4982>] iterate_supers+0xb2/0x110
[11172.459404]  [<ffffffff81212165>] sys_sync+0x35/0x90
[11172.459407]  [<ffffffff8178a3ad>] system_call_fastpath+0x1a/0x1f
[11292.591308] INFO: task extlinux:8675 blocked for more than 120 seconds.
[11292.591312]       Not tainted 3.16.0-30-generic #40-Ubuntu
[11292.591313] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[11292.591314] extlinux        D ffff88082fa13840     0  8675   8674 0x00000000
[11292.591318]  ffff8807d3117d70 0000000000000082 ffff880743fe1e90 0000000000013840
[11292.591320]  ffff8807d3117fd8 0000000000013840 ffff880743fe1e90 ffff8807d3117e98
[11292.591322]  ffff8807d3117e90 7fffffffffffffff ffff880743fe1e90 ffff880743fc2868
[11292.591324] Call Trace:
[11292.591330]  [<ffffffff81785509>] schedule+0x29/0x70
[11292.591333]  [<ffffffff817847c9>] schedule_timeout+0x229/0x2a0
[11292.591336]  [<ffffffff8108b256>] ? __queue_work+0x136/0x340
[11292.591338]  [<ffffffff8108b52a>] ? __queue_delayed_work+0xaa/0x1c0
[11292.591340]  [<ffffffff81786694>] wait_for_completion+0xb4/0x1e0
[11292.591345]  [<ffffffff810a5670>] ? wake_up_state+0x20/0x20
[11292.591350]  [<ffffffff81211ed0>] ? vfs_fsync+0x40/0x40
[11292.591353]  [<ffffffff8120b355>] sync_inodes_sb+0xa5/0x1c0
[11292.591355]  [<ffffffff81211ed0>] ? vfs_fsync+0x40/0x40
[11292.591357]  [<ffffffff81211ee9>] sync_inodes_one_sb+0x19/0x20
[11292.591360]  [<ffffffff811e4982>] iterate_supers+0xb2/0x110
[11292.591363]  [<ffffffff81212165>] sys_sync+0x35/0x90
[11292.591366]  [<ffffffff8178a3ad>] system_call_fastpath+0x1a/0x1f
[11412.723268] INFO: task extlinux:8675 blocked for more than 120 seconds.
[11412.723272]       Not tainted 3.16.0-30-generic #40-Ubuntu
[11412.723273] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[11412.723274] extlinux        D ffff88082fa13840     0  8675   8674 0x00000000
[11412.723277]  ffff8807d3117d70 0000000000000082 ffff880743fe1e90 0000000000013840
[11412.723279]  ffff8807d3117fd8 0000000000013840 ffff880743fe1e90 ffff8807d3117e98
[11412.723281]  ffff8807d3117e90 7fffffffffffffff ffff880743fe1e90 ffff880743fc2868
[11412.723283] Call Trace:
[11412.723290]  [<ffffffff81785509>] schedule+0x29/0x70
[11412.723292]  [<ffffffff817847c9>] schedule_timeout+0x229/0x2a0
[11412.723295]  [<ffffffff8108b256>] ? __queue_work+0x136/0x340
[11412.723297]  [<ffffffff8108b52a>] ? __queue_delayed_work+0xaa/0x1c0
[11412.723300]  [<ffffffff81786694>] wait_for_completion+0xb4/0x1e0
[11412.723304]  [<ffffffff810a5670>] ? wake_up_state+0x20/0x20
[11412.723308]  [<ffffffff81211ed0>] ? vfs_fsync+0x40/0x40
[11412.723311]  [<ffffffff8120b355>] sync_inodes_sb+0xa5/0x1c0
[11412.723313]  [<ffffffff81211ed0>] ? vfs_fsync+0x40/0x40
[11412.723315]  [<ffffffff81211ee9>] sync_inodes_one_sb+0x19/0x20
[11412.723318]  [<ffffffff811e4982>] iterate_supers+0xb2/0x110
[11412.723320]  [<ffffffff81212165>] sys_sync+0x35/0x90
[11412.723324]  [<ffffffff8178a3ad>] system_call_fastpath+0x1a/0x1f
mirto@mirto-P650SE:/Mio/ISO/kubuntu/14.10$