Couple of things - In terms of using these for a server - the 3040’s are pretty light on specs and doubt they would have enough grunt to do it justice. For a bridge - the 2G/8G versions seem to cope just fine with using the server OS - ie no GUI to take resources. There are other thin clients for sure but the 3040 just looked the right size and is super neat - I always hated how the power for the pi has to come in from the side…
In terms of WIFI - if you need it then it may just require some questions to be asked of the seller. Finding model numbers of those with and without wifi seems to be scarce. However the model I am using is “N10D” running off 5V if that helps. Get the seller to show a picture of the back of the unit - if it has wifi it will show BOTH a MB Mac# and the WLAN Mac# - a solid indication that it was shipped with wifi so long as no one removed the option. Adding a dongle may work - as with most linux installs, things just work unlike windows - just be sure to use one that works with linux and have it plugged in on install so it is seen up front.
So in terms of resetting the bios - there seems to be a fairly common procedure of a hardware reset - on Dell desktops there is a jumper to remove prior to boot. For the 3040 Thinclient, there’s a button near the battery on the board labeled PWCLR. The trick is to hold down the PWCLR button while powering up the system. It’ll show a text mode screen indicating the passwords have been disabled. You can then power off, release the button and then you’ll have a clear BIOS. Yes it will require opening up the unit but seems straight forward by just removing the back cover. Couple of reference post links:
I will be honest, i got this so cheap and the purchase was literally a hail mary to see if i could even get this to work. I definitely lucked out on getting one with wifi - I just ordered a second unit hopefully it has wifi also!! Ensure they provide a power adapter too - otherwise more stuffing around.
These are solid little units and you may just need to be patient to find one that comes up on ebay with all the goods - I am pretty confident that mine was from a seller who bought a commercial lot from an old business that upgraded things.