Well there isn't any current functionality for updating the cards, so they're right when they say it can't. In the future, their words might change though.
There is functionality, and it works.. the public just isnt aware of how they will do it, but that doesnt means it wont happen.... For the 1000th time GW team have been totally transparent with their motives/actions/updates, its even in plain english on the site.. People just dont have to buy into Rubbish that a R4i Fanboy Reseller said (aliexpress even. must be true.. and the fact he only stocked the clones...)
But when there is nothing better too do, how about multiple pages of conjecture...
People considered they may have needed a FPGA update for CARD2 considering the carts original instruction was read only, so NAND Saving demo was proof ??
Multirom support is probably the hardest feature of all to implement in such, the red cart doesn't have any file system support as it is, its emulating a retail cart from an image, On top of that also needs a sane switching method, and possibly save redirection to the microsd if its wanted by alot of users. Considering the time from GWs release till now and its still a WIP, it takes time and effort, imagine if all users that complain, combined together to put the effort they use to bitch and whine to learn and do something productive to forward progress, you would be running all off a SD by now
"Note: User feedback for GW2.0b2 has been overwhelmingly positive. The absolute stability of our beta menu system was an important milestone for us prior to pushing out the FPGA update required for some of the new features."
"As you can imagine, both these features required a major revamp of our hardware's internal firmware, something we had known and planned for from day one so rest assured, unlike others, GW3DS is a fully featured and FULLY updatable hardware design. Our policy has and will always be to stick by our customers and ensure they get value for their money."