2) in order to revert to the original firmware if I brick the device, I need a copy of the firmware. Unfortunately Linksys doesn't seem to have ever produced an update to firmware and the original firmware doesn't provide a method of backing itself up (just allows settings to be backed up).
As to Linksys stock firmware for the 610n, I honestly have no idea... I'm sure there is a copy out there on the internet somewhere (maybe call Linksys and see if they can provide it - they just may not put it on their website anymore because of how old it is).
I still have and use a 610n v1 myself (with DD-WRT) - works great for media streaming.
EDIT: Here is a link to stock Linksys firmware from right on this site (no idea if it's the latest or not):
EDIT2: Actually, there are later versions in that thread, including a post with links to Linksys-hosted versions of the firmware (start at the end of the thread and work backwards). _________________ 1 x Linksys WRT160n v3
1 x Linksys WRT310n v1
1 x Linksys WRT600n v1.1
1 x Linksys WRT610n v1
1 x Linksys E2500
1 x Netgear WNDR3300
1 x Dlink DIR-825 v1
2 x Asus RT-AC66U
I'm fixing the ftp links. Note: the old 'eko' builds are gone (as the wiki already states), but the old links remain for history and archive.org purposes. Thanks @jtrosky for the OEM f/w link; also added to the wiki. _________________ #NAT/SFE/CTF: limited speed w/ DD#Repeater issues#DD-WRT info: FAQ, Builds, Types, Modes, Changes, Demo#
OPNsense x64 5050e ITX|DD: DIR-810L, 2*EA6900@1GHz, R6300v1, RT-N66U@663, WNDR4000@533, E1500@353,
WRT54G{Lv1.1,Sv6}@250|FreshTomato: F7D8302@532|OpenWRT: F9K1119v1, RT-ACRH13, R6220, WNDR3700v4