I've had two BT Home Hubs now and I've just managed to recover them both with the pointers given by a geek on the BT Home Hub technical support line. Top marks to whomever that was but it was EXTREMELY difficult to talk to somebody that knew what they were talking about. My home hub(s) were white bricks after BT attempted to update them remotely (6.1.1M -> 6.1.1R) but these steps recovered the Home Hub and they both now work.
These steps reset the home hub and reinstall the firmware that's on the CD back onto the Home Hub. i.e. this is Home Hub brain surgery. Use at your own risk.
This is the recipe to recover the home hub but I'm not guaranteeing anything:
High Level
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a) Reset Home Hub into 'Kernel Recovery' mode
b) Connect your Home Hub and PC with an ethernet cable
c) Reflash firmware from utilities supplied by BT
d) Reconnect your Home Hub to BT ADSL
e) Wait for BT to update your firmware
f) Reconfigure your router
Do NOT skip any steps in section (a). Not even one step. Read the whole detailed recipe first and get help if you don't understand a step or don't have the CD. After section (d), your Home Hub should be back and working with the factory default settings and connected to ADSL again.
Detailed
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a) Reset Home Hub into 'Kernel Recovery' mode
a.1) Turn on your BT Home Hub
a.2) Wait for the lights to settle down. OK, give it 5 minutes to settle down.
a.3) Press the 'Wireless Association' button on the back of the Home Hub for 15seconds
a.4) WHILE YOU HAVE THE BUTTON PRESSED, PULL OUT THE POWER LEAD
a.5) Wait for 30s. You can stop pressing the button while the power is off
a.6) Hold down the 'Wireless Association' button and plug the power lead back into the Home Hub
a.7) Wait for the lights to settle down (15s).
a.8) Release the Wireless Association button
a.9) Unplug the Home Hub from the ADSL connection (i.e. take out the 'Broadband In' cable but NOT any ethernet cables)
b) Connect your Home Hub and PC with an ethernet cable
b.1) If they're not connected then connect your Home Hub and PC DIRECTLY with an Ethernet cable. It's possible to do this recovery over USB (it worked for me) but see below for the USB connection steps
b.2) The data light on the Home Hub should light up but don't worry if it doesn't
b.3) Assign the fixed IP address of 192.168.1.100, netmask 255.255.255.0, g/w 192.168.1.254, primary DNS of 192.168.1.254 (ALL must be configured) to the Ethernet interface that's connected to the Home Hub. If that interface is a dynamic USB interface then assign these addresses to the USB interface.
c) Reflash firmware from utilities supplied by BT
c.1) Insert your BT Home Hub CD into the computer's CDROM drive
c.2) Navigate to the directory called 'Utils\UpgradeWizard\UpgradeBT\'.
c.3) Run 'upgradeBThub.exe'
c.4) Click 'Next'
c.5) If your Home Hub is not discovered then turn it off and wait for 2 minutes then go back to step a.1 It took me five (5) attempts to get the Hub discovered. Don't try to cut down on the timings.
c.6) Keep clicking 'Next' until the firmware is downloaded (takes < 10 minutes)
c.7) Your Home Hub now has the factory default settings with the firmware version that came with your Home Hub
d) Reconnect your Home Hub to BT ADSL
d.1) Plug the ADSL connection back into 'Broadband In'
d.2) Reset your Ethernet interface to use a dynamic IP address not the fixed 192.168.1.100 address
e) Wait for BT to update your firmware
e.1) Don't reconfigure your Home Hub. It was my reconfiguration that caused the Home Hub update (6.1.1M -> 6.1.1R) from installing successfully
e.2) You might want to turn off the Wireless connectivity because anything could currently connect to it. You can access the Home Hub at
http://192.168.1.254 e.3) Leave the Home Hub turned on and connected to ADSL overnight. BT will update your Home Hub remotely. Mine was done the night after I recovered it but maybe wait two nights
f) Reconfigure your router
f.1) Perform any reconfiguration, probably at your own risk. The remote download doesn't seem to like my reconfiguration steps :-D
Additional USB steps
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BEWARE: This section is from guesswork, not assistance from BT
i) Navigate to the directory 'Utils\USB Drivers' on the CD
ii) Run 'BTHomeHub_USB.exe'
iii) Reboot your PC
iv) Connect your PC and Home Hub with a USB cable
If you are recovering your Home Hub then stop here and go back to step b.2 above
v) If you're lucky then the PC will recognise the Home Hub as a Thompson ST USB device connected via RNDIS (yeuch !!)
vi) You'll get a new network connection that connects you to the Home Hub and the Hub will assign an IP address to the connection