CDMA Modem is not working anymore after upgrade

[leledumbo]

The modem previously works on 11.10, but now even it's not detected. There's no ttyUSB* entry under /dev. However, lsusb seems to find it and it's already switched to modem mode. Here's the output:

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 003: ID 046d:c045 Logitech, Inc. Optical Mouse
Bus 001 Device 011: ID 0fce:e166 Sony Ericsson Mobile Communications AB
Bus 001 Device 005: ID 0930:6545 Toshiba Corp. Kingston DataTraveler 102 Flash Drive / HEMA Flash Drive 2 GB / PNY Attache 4GB Stick
Bus 002 Device 006: ID 19d2:ffdd ZTE WCDMA Technologies MSM <-- Here is the modem

Please tell me how to solve this (if somebody already has the answer)

[Snowhog]

Is this the case -- modem not working -- if you have it plugged in when your power-on the PC? And maybe more pertinent, have you done a reboot since the upgrade?

[leledumbo]

Done that, no effect. I've tried plugging in on power on, on after login, plug in-out-in, all to no avail. I've done a lot of reboot as well since I have to go back to my windows to get internet access (I only have it through this CDMA modem)

[leledumbo]

dmesg output just right after I insert the USB modem:

[ 414.646565] scsi 4:0:0:0: CD-ROM EVDO ReV A 7.00 PQ: 0 ANSI: 2
[ 414.650100] sr1: scsi-1 drive
[ 414.650565] sr 4:0:0:0: Attached scsi CD-ROM sr1
[ 414.651093] sr 4:0:0:0: Attached scsi generic sg2 type 5
[ 414.948194] usb 2-1.5: USB disconnect, device number 3
[ 417.192567] usb 2-1.5: new full-speed USB device number 4 using ehci_hcd
[ 417.264682] usb 2-1.5: device descriptor read/64, error -32
[ 417.464330] scsi5 : usb-storage 2-1.5:1.3
[ 418.465697] scsi 5:0:0:0: Direct-Access EVDO ReV A 7.00 PQ: 0 ANSI: 0 CCS
[ 418.466565] sd 5:0:0:0: Attached scsi generic sg2 type 0
[ 418.470391] sd 5:0:0:0: [sdb] Attached SCSI removable disk

so it looks like the USB modem goes to /dev/sdb, the mode switch seems working though. could anyone explain what this means?