@Virgo The issue is not so much about "negotiating" the speed, which is anyway only supported over BaseT. It is that it will not accept setting 'Link Speed - Auto' in Profile Overrides! The only way to get it to work is to manually set the port link speed to 1Gig (and 10 is default)... 

According to this thread, firmware 1.0.1 should have fixed this, but apparently not... TL-SX3008F doesn't auto negotiate to 1G with SFP

If it doesn't recognize the module, which I doubt would be the case with Cisco modules, I don't see why it couldn't anyway try setting a different link speed until it works... All it needs to know is that there is a module in the cage... And if it's a DAC cable (passive copper), again all it would need to do is to test at 1 Gig if 10 Gig doesn't work... 

And just so you know, the 3008F has SFP cages only, meaning that you can't connect an Ethernet cable unless you plug in an RJ45-module. And, as I wrote, I have tested with various SFP modules including different Fiber and DAC models. The only Ethernet modules I tested were Cisco SFP+ which will auto negotiate normally and are capable of both 1 and 10Gig. The fiber modules are obviously 1Gig versions, and the idea is that the switch would set itself to 1Gig when such a module is detected. It's not negotiating a speed with the other party... 

Anyway, all my testing is between switches in-rack (less than 50cm) and to the SFP port of a TL-SG2428P, or to a 1 Gbit Eth port on that switch in the case of the Cisco module.