После смены матери перестали монтироваться USB-flash накопители.

Ты уверен что твоя флешка это sda1 ? Покажи хвост dmesg'а

Вот все, что в dmesg что нашел про usb
usb.c: registered new driver usbdevfs
usb.c: registered new driver hub
usb-uhci.c: $Revision: 1.275 $ time 23:24:22 Apr 29 2003
usb-uhci.c: High bandwidth mode enabled
PCI: Found IRQ 10 for device 00:07.2
IRQ routing conflict for 00:07.2, have irq 11, want irq 10
IRQ routing conflict for 00:07.3, have irq 11, want irq 10
PCI: Sharing IRQ 10 with 00:08.0
usb-uhci.c: USB UHCI at I/O 0xd400, IRQ 11
usb-uhci.c: Detected 2 ports
usb.c: new USB bus registered, assigned bus number 1
hub.c: USB hub found
hub.c: 2 ports detected
PCI: Found IRQ 10 for device 00:07.3
IRQ routing conflict for 00:07.2, have irq 11, want irq 10
IRQ routing conflict for 00:07.3, have irq 11, want irq 10
PCI: Sharing IRQ 10 with 00:08.0
usb-uhci.c: USB UHCI at I/O 0xd800, IRQ 11
usb-uhci.c: Detected 2 ports
usb.c: new USB bus registered, assigned bus number 2
hub.c: USB hub found
hub.c: 2 ports detected
usb-uhci.c: v1.275:USB Universal Host Controller Interface driver
usb.c: registered new driver hiddev
usb.c: registered new driver hid
hid-core.c: v1.8.1 Andreas Gal, Vojtech Pavlik <vojtech@suse.cz>
hid-core.c: USB HID support drivers


а вот, еще:

hub.c: new USB device 00:07.2-1, assigned address 2
usb_control/bulk_msg: timeout
usb.c: USB device not accepting new address=2 (error=-110)
hub.c: new USB device 00:07.2-1, assigned address 3
usb_control/bulk_msg: timeout
usb.c: USB device not accepting new address=3 (error=-110)
hub.c: new USB device 00:07.2-1, assigned address 4
usb_control/bulk_msg: timeout
usb.c: USB device not accepting new address=4 (error=-110)
hub.c: new USB device 00:07.2-1, assigned address 5
usb_control/bulk_msg: timeout
usb.c: USB device not accepting new address=5 (error=-110)
Initializing USB Mass Storage driver...
usb.c: registered new driver usb-storage
USB Mass Storage support registered.
uhci.c: USB Universal Host Controller Interface driver v1.1
via82cxxx: timeout while reading AC97 codec (0x9A0000)
i8253 count too high! resetting..

Что то похожее на конфликт прерываний нарисовалось, или я не прав?