Losing USB-HDD / Not found during reboot

[odoll]

SheevaPlug with DNEX u-boot 2011.12-3 running Debian Squeeze from SD, Hitachi SimpleDrive 3 http://www.hitachigst.com/support/index-files/sd3-technical-support connected to USB

I have the odd problem that the plug sometimes loses the attached USB-HDD. A simple reboot is not good enough to mitigate the situation

Though an
root@Share:~# lsusb
Bus 001 Device 002: ID 4971:ce23 SimpleTech
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
shows it, it can't be mounted (no device /dev/sXY)

Only solution is to power cycle both the plug and the USB-HDD (which is hard to be done from remote )

Can I rescan / reinitiate the Plugs' USB-Port for new devices from Squeeze?

[odoll]

PS: re dmesg all looks OK!?

root@Share:~# dmesg | grep usb
[   23.289934] usbcore: registered new interface driver usbfs
[   23.307227] usbcore: registered new interface driver hub
[   23.317289] usbcore: registered new device driver usb
[   23.407347] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
[   23.414191] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[   23.421464] usb usb1: Product: Marvell Orion EHCI
[   23.426191] usb usb1: Manufacturer: Linux 2.6.32-5-kirkwood ehci_hcd
[   23.432587] usb usb1: SerialNumber: orion-ehci.0
[   23.438116] usb usb1: configuration #1 chosen from 1 choice
[   23.771367] usb 1-1: new high speed USB device using orion-ehci and address 2
[   23.932385] usb 1-1: New USB device found, idVendor=4971, idProduct=ce23
[   23.939133] usb 1-1: New USB device strings: Mfr=10, Product=11, SerialNumber=3
[   23.946510] usb 1-1: Product: SimpleDrive III by Hitachi
[   23.951864] usb 1-1: Manufacturer: HitachiGST
[   23.956239] usb 1-1: SerialNumber: D31094610C17
[   23.966737] usb 1-1: configuration #1 chosen from 1 choice
[   24.163537] usbcore: registered new interface driver usb-storage
[   24.170209] usb-storage: device found at 2
[   24.170218] usb-storage: waiting for device to settle before scanning
[   29.161717] usb-storage: device scan complete

[odoll]

BTW: later the year the issue even got worse as the USB drive often wasn't found though rebooting and or resetting the plug. In the end I even electrically connected the outer shield of the USB-plug to the earth cable, which gave some relief.
While I'm currently trying to update my plug from Squeeze to Wheezy I'm playing around with images on different SHDC cards (old Panasonic vs new Transcend). Looking at the various reboots performed during this exercise I notice, that not only the Transcend card is found immediately - usually I have to press the reset button for the Panasonic to be recognized by the plug - but also the USB drive recognition is perfect again with the Transcend, while it's still bad, when the Panasonic is connected.

Strange, but there seems to be some correlation of the recognition with the SD card's brand and the same USB drive!?