Openwrt TP Link Archer C50 v4

Hello people
I have a TP Link Archer c50 V4 (4.2 to be more precise) and every image I try to play on the router returns saying that it was not accepted by the device.
Anyone have any tips?

Try the TFTP method

Did you follow the instructions to build an image for TFTP use?

Update: I just realised all my dropbox shared folders have been disabled, including those for the prebuilt images for C50 v4/v5 linked in the C50 wiki page. They return Error 404.

Update 3 I've added a new link to the C50 wiki page to a temporary dropbox mirror of the contents of my disabled dropbox folder for C50v4/v5.