Updating 5D3 firmware on Mac

My 5D3 is running 4.0.4 [14.33.96182]. It says I need to update it, but every time I try, it says cannot connect to the server. I went to the 5D3 support page, and there is no link there for a Mac disk image of the current firmware. Is the new firmware PC only?

The dashboard’s ‘autoupdater’ doesn’t always work. Have you checked the 5D3 support page? It has the manual firmware link and instructions.

No Mac disc image there. Just some sort of .tdf file for PCs I guess.

That TDF file is the firmware you seek. Simply follow the ‘Manual Firmware Update Instructions’ and update it via the dashboard.