For a variety of reasons too lengthy to go into, I decided to reformat the standard 500Gb internal hard drive after copying all my recordings to an external USB drive. The internal reformat command failed because "The capacity is too large".

Is there a way to force a format via the CFW? If so, what command do I use?

Thanks for any help.
Reboot and retry.
I did so and the machine immediately asked to format the drive. It did so, apparently successfully, reporting disk space as: Available 427.4, Used 20.2, Reserved 72.4, Total 500.0. I was able to make and play back a short test recording.

Possibly unwisely, I didn't leave well alone but ran fixdisk in maintenance mode. This immediately produced screen after screen of various errors, most of which scrolled by too quickly to read. After about 18 hours, it stopped with the following message:
Block #1050018 (25850733) causes directory to be too big.  CLEARED.                                                                                               
Illegal block #1050036 (1439593953) in inode 58743.  CLEARED.                                                                                                     
Error storing directory block information (inode=58743, block=0, num=1018464): Memory allocation failed                                                           
hmx_int_stor: ***** FILE SYSTEM WAS MODIFIED *****                                                                                                                 
hmx_int_stor: ***** FILE SYSTEM WAS MODIFIED *****                                                                                                                 
tee: /tmp/fix-disk.log: I/O error                                                                                                                                 
Removing extra swap space.                                                                                                                                         
cat: write error: No space left on device                                                                                                                         
fix-disk: session terminated with exit status 0                                                                                                                   
Press return to continue:

I have no idea where this leaves me and how to proceed, so any advice would be appreciated.

Also, when I rebuilt the webif, I was able to reinstall all previously installed packages except new-portal. This produced:
>>> opkg install new-portal
Installing new-portal (1.01) to root...
Collected errors:
 * satisfy_dependencies_for: Cannot satisfy the following dependencies for new-portal:
 *     mongoose (>= 3.0-5) *
 * opkg_install_cmd: Cannot install package new-portal.


Again, advice welcome.
Did you visit the link in post 3?

Unfortunately, I saw post 2 and acted on it before post 3 was posted. I'd really appreciate an explanation for the output I posted, and advice on whether it's now essential to go through the RMA/reformat routine, which would involve reinstalling and reconfiguring the webif from scratch.
I have a similar problem with the new portal after a new 2Tb disk install. I installed the hard disk in the Humax and accepted the disk format pop-up on the Tv screen, everything seemed to go OK but I cannot get the new portal to install, getting the same fault info ref mongoose as above in post 4 part 2. If I return to RMA will the Humax require the old 500Gb disk installed first or will it just not recognise the larger disk.

Web interface version: 1.4.0-3
Custom firmware version: 3.10 (build 2734)
Humax Version: 1.03.12 (kernel HDR_CFW_3.10)
Loader Version: a7.33
I have re-packaged new-portal and removed the dependency on mongoose. If you update your package list you should be able to install it now.
I am not able to get new-portal to install

>>> opkg install new-portal
Installing new-portal (1.01-1) to root...
Collected errors:
 * check_conflicts_for: The following packages conflict with new-portal:
 * check_conflicts_for: 	portal-xtra1 * 
 * opkg_install_cmd: Cannot install package new-portal.


Portal-xtra1 is not listed to uninstall.

Sent from my iPad using Tapatalk