It seems to not work on any sizes for the upload. I have completed the download test and have no problem with that. When I select the test this is what I see on the screen in a box:
Be Patient Uploading 33MB of data [stop] Flashing
Testing your connection with Custom :: Forwarding Disabled...
Did you know... flash based speed tests are notoriously inaccurate?
Unique to the Internet TestMy.net uses only your web browser.
Mozilla/5.0 (Windows NT 6.1; rv:20.0) Gecko/20100101 Firefox/20.0
On my tab title bar of my web browser it is showing me a connecting... title and when I hover over anything on that screen except for stop my mouse cursor is a loading image. I am running Firefox on Windows 7 ISP is Verizon. Let me know what other informaiton y'all might need to help with this thing.