The board partners aren't allowed to ship cards with a modified BIOS and they will all stick to this rule because nobody wants to be punished with lower supply. However, we did notice that ASUS is advertising two GeForce GTX 1070 Ti cards with overclocked frequencies. So what's going on here?
The answer can be found at VideoCardz. The site points out that these ASUS cards do not have a modified BIOS. ASUS is advertising the frequencies of the OC Mode, which is achieved via the company's GPU Tweak App. Manufacturers aren't allowed to factory overclock via BIOS modifications, but there's nothing that prevents them from doing software overclocks.
So manufacturers who have overclocking utilities can provide higher frequencies with a single click, but those who don't have these tools have a problem. VideoCardz noticed Zotac tries to get around this problem by advertising its cards are capable of hitting higher clockspeeds, but consumers have to do the overclocking manually:
So the only solution was to advertise factory tested overclocking. This basically tells customers that AMP Extreme guarantees +150 MHz GPU and 200 MHz Memory overclocking. The new part is where the customer has to do this manually.