[Galaxy S II Original Android Development] maczaros:
Sometimes loosing phone signal (only emmergency) while phone call or right after disconnecting.

Hapened on 3.0.1 and still in 3.1.

In catlog I think most importatn is:

04-10 19:44:47.780 D/UsbHostManager(2930): onUEvent(device) :: action = remove, devtype = usb_interface, device = /proc/bus/usb/001/002, product = 1519/20/1311, type = 2/0/0, interface = 2/2/1, devpath = /devices/platform/s5p-ehci/usb1/1-2/1-2:1.0
04-10 19:44:47.785 D/UsbHostManager(2930): onUEvent(device) :: action = remove, devtype = usb_interface, device = /proc/bus/usb/001/002, product = 1519/20/1311, type = 2/0/0, interface = 10/0/0, devpath = /devices/platform/s5p-ehci/usb1/1-2/1-2:1.1
04-10 19:44:47.795 D/UsbHostManager(2930): onUEvent(device) :: action = remove, devtype = usb_interface, device = /proc/bus/usb/001/002, product = 1519/20/1311, type = 2/0/0, interface = 2/2/1, devpath = /devices/platform/s5p-ehci/usb1/1-2/1-2:1.2
04-10 19:44:47.800 D/UsbHostManager(2930): onUEvent(device) :: action = remove, devtype = usb_interface, device = /proc/bus/usb/001/002, product = 1519/20/1311, type = 2/0/0, interface = 10/0/0, devpath = /devices/platform/s5p-ehci/usb1/1-2/1-2:1.3
04-10 19:44:47.810 D/UsbHostManager(2930): onUEvent(device) :: action = remove, devtype = usb_interface, device = /proc/bus/usb/001/002, product = 1519/20/1311, type = 2/0/0, interface = 2/2/1, devpath = /devices/platform/s5p-ehci/usb1/1-2/1-2:1.4
04-10 19:44:47.820 D/UsbHostManager(2930): onUEvent(device) :: action = remove, devtype = usb_interface, device = /proc/bus/usb/001/002, product = 1519/20/1311, type = 2/0/0, interface = 10/0/0, devpath = /devices/platform/s5p-ehci/usb1/1-2/1-2:1.5
04-10 19:44:47.825 D/UsbHostManager(2930): onUEvent(device) :: action = remove, devtype = usb_interface, device = /proc/bus/usb/001/002, product = 1519/20/1311, type = 2/0/0, interface = 2/2/1, devpath = /devices/platform/s5p-ehci/usb1/1-2/1-2:1.6
04-10 19:44:47.835 D/UsbHostManager(2930): onUEvent(device) :: action = remove, devtype = usb_interface, device = /proc/bus/usb/001/002, product = 1519/20/1311, type = 2/0/0, interface = 10/0/0, devpath = /devices/platform/s5p-ehci/usb1/1-2/1-2:1.7
04-10 19:44:47.850 E/UsbHostManager(2930): usbDeviceRemoved :: deviceName = /dev/bus/usb/001/002
04-10 19:44:47.860 D/dalvikvm(7567): GC_CONCURRENT freed 384K, 6% free 9761K/10375K, paused 7ms+12ms
04-10 19:44:47.900 V/WindowOrientationListener(2930): nearestRotation : 0 Angle: 10 tilt: 9
04-10 19:44:47.960 D/UsbHostManager(2930): usbDeviceAdded : device :: /dev/bus/usb/001/003 [1519h:0020h] [02h,00h,00h] (CDC Control)
04-10 19:44:47.960 D/UsbHostManager(2930): usbDeviceAdded : interface :: /dev/bus/usb/001/003 [1519h:0020h] [02h,02h,01h] (CDC Control)
04-10 19:44:47.960 D/UsbHostManager(2930): usbDeviceAdded : interface :: /dev/bus/usb/001/003 [1519h:0020h] [0ah,00h,00h] (CDC Data)
04-10 19:44:47.960 D/UsbHostManager(2930): usbDeviceAdded : interface :: /dev/bus/usb/001/003 [1519h:0020h] [02h,02h,01h] (CDC Control)
04-10 19:44:47.960 D/UsbHostManager(2930): usbDeviceAdded : interface :: /dev/bus/usb/001/003 [1519h:0020h] [0ah,00h,00h] (CDC Data)
04-10 19:44:47.960 D/UsbHostManager(2930): usbDeviceAdded : interface :: /dev/bus/usb/001/003 [1519h:0020h] [02h,02h,01h] (CDC Control)
04-10 19:44:47.960 D/UsbHostManager(2930): usbDeviceAdded : interface :: /dev/bus/usb/001/003 [1519h:0020h] [0ah,00h,00h] (CDC Data)
04-10 19:44:47.960 D/UsbHostManager(2930): usbDeviceAdded : interface :: /dev/bus/usb/001/003 [1519h:0020h] [02h,02h,01h] (CDC Control)
04-10 19:44:47.970 D/UsbHostManager(2930): usbDeviceAdded : interface :: /dev/bus/usb/001/003 [1519h:0020h] [0ah,00h,00h] (CDC Data)

Full catlog at http://pastebin.com/yPs3fqUi

EDIT: On stock or CFroot kernel problem above doesn't exist.