Alrighty ... a few "gotcha's" ...
#1 - Upon login on a DIR-3040 running pre f/w 1.13, a popup dialog appears *forcing* an upgrade to the latest firmware even though the Automatic Upgrade option was disabled. Pressing the ESC key on the keyboard causes the firmware update to abort/cancel and the DIR-3040 proceeds to "soft-brick". Workaround is to leave the firmware update page open, connect to the Internet using one's backup router, downloading f/w 1.13_HOTFIX, and manually uploading the Step-2 1.13_Hotifx (bypassing Step-1 1.12_Hotifx) to the failed DIR. In other words, take the update like-it-or-not.
#2 - Throw away all the older f/w releases; the 1.13 release notes explicitly state that rolling back to a previous f/w version *will not be* possible.
#3 - Hope to whatever almighty diety one worships that you manually copied all of the DIR-3040 property page settings to a document; most notably any IP reservations. After upgrading to the latest f/w, some of the devices that had reserved IP addresses no longer appear in the Connected Devices page. One cannot re-enter the same reservation as it indicates that it has already been reserved. Workaround is to factory reset the DIR-3040 and re-enter all the configuration settings manually. Reloading a previous f/w config *does not* solve the issue and introduces instability.
#4 - I would *not* advise restoring a previous config; manually re-enter your settings.
#5 - The Connected Devices page is a rollercoaster ride, 40% of the time the devices assigned via DHCP will not appear and the reserved IP devices often appear as offline (greyed out).
#6 - The logs contain the username and password in clear text. If you're sending the device logs to yourself via email, make triple certain that you put in the correct email address information. As the log fills quickly with failed path:/var/run/mdnsd Socket:26 Err:-1 entries, you'll need to search for username to find the information. When downloading directly, the log file is now named messages.bin but can be opened in a text editor for viewing.
#7 - F/W 1.13 Build 03 is the latest version. Unfortunately, the DIR-3040 UI *does not* display build versions and the D-Link websites (TW vs US vs CDN) contain a few version of F/W 1.13. Pay close attention to the release dates to ensure that are downloading the latest version.