The state of plug and play

Today I finally managed to configure my VOIP adapter, a Grandstream Handytone 286. Mind you, it was not easy, to say the least. And that's considering I am a graduate software engineer with 7 years of professional experience; the only way you have a chance is if you fully understand XKCD.
The first strange issue was that my router, a Netgear WPN824, crashed when I plugged the VOIP adapter into it. My first idea was to check if it had the latest firmware; the update system said so, and I went on. Since I had some problems with some VOIP providers and my softphone, and some reports on the Internet said that the firewall could crash the router, I tried to set the adapter in the DMZ. Since my router could only take one server in the DMZ, I had to disable DHCP and manually setup the address, which involved typing the MAC address in the router configuration. As that didn't work -I guess I would have needed to force the expiration of the DHCP address in the adapter- I had to set it statically in the adapter too.
It was really fun to find that the problem was still there: the bloody adapter still crashed the bloody router. I still had a couple of tricks left. I tried disable UPnP, which I read it also caused problems, but to no avail. I was thinking of setting up some port triggering, but I thought that if setting the adapter in the DMZ didn't work, port triggering would be quite useless too.
Going around the router documentation I come across some firmware downloads. I see the versions available and with the corner of the eye I see something strange: the latest version number seems to be different than the one I saw in my router. Fiddling a bit I check and, indeed, I had an old firmware version. All I had to do is a firmware upgrade.
For those of you who have never done it, firmware upgrades is something that really makes a person nervous. If something goes wrong you turn a piece of hardware into a nice decorative ornament; there is no undo, no turning back, it is the point of no return, you cross the Rubicon, you burn the bridges, etc.
Fortunately, the firmware upgrade worked OK and the router no longer crashed. So all I had to configure was the SIP address, the STUN server, the works. That was pretty simple in comparison.
In case you didn't notice the irony of plug and play, I included 11 very technical terms just to configure a bloody VOIP adapter, which took me 2 hours and lots of guesswork to make it work