Fix or Workaround for R6700v3 DHCP management interface bug?

[T_C_]

Does there exist a fix or workaround for the bug in the DHCP management interface that prevents altering the address range on an R6700v3?

We have an R6700v3 in service, that is configured to dynamically-assign addresses .150 through .253.  When one attempts to reduce that range -- say to .150 through .199 -- the web-based management interface incorrectly complains that "The IP address conflicts with the WAN IP subnet. Please enter a different IP address."

That message is obviously wrong, because the range is being reduced, and therefore the new configuration cannot conflict with anything that the existing configuration does not conflict with.  It's also wrong because the WAN IP subnet in this instance is a completely different subnet from the one which is dynamically-assigned -- so again, conflict is impossible.  In fact, the interface is so broken that even if the user deselects "Use Router as DHCP server" and attempts to disable DHCP, the same invalid error message is displayed.

This is an incredibly sloppy bug written by Netgear, and it has persisted for some years, since this obviously is not a brand-new router. The device in-question is running the current firmware release ( V1.0.4.128_10.0.104 ).  Are there any plans to patch this bug?  Is there any other way to alter the DHCP range, to workaround Netgear's broken interface?  Or are these routers just e-waste when reconfiguration is required?

There is nothing wrong with the existing configuration of this router -- it has been in-place and functioning for several years.  The DHCP range reduction is merely to increase the availability of static addresses on that subnet.

Thanks in advance.

[FURRYe38]

There a reason why you need that range? 

Does setting .100 to .200 work? 

I believe this model router being of some age may no longer be in active development and probably has gone into EoL status. Might look at 3rd party FW to see if they support it, if no, time to find something newer. 

[T_C_]

No, that range does not work either.  No changes can be made to the configuration -- DHCP cannot even be disabled, as I described.

So, basically, this router is electronic waste if the configuration needs to be changed, because Netgear wrote egregious bugs and never bothered to fix them.  Well done Netgear.

[FURRYe38]

If you disconnect the router from any WAN connections and LAN devices accept for the one wired PC, factory reset and setup from scratch, by pass the checking for internet services, manually setup, get to the home screen, can you then change the IP address range at all?