Remember how Shimano gave Hammerhead Karoo/Karoo 2 owners the shaft back in May? That has been corrected, at least for Karoo 2 users, by an enterprising fellow named Valter Costa who leveraged the Hammerhead SDK to add the functionality back into the device via an add-in.
I haven’t had a chance to really dig into the code, so I’m not sure exactly how it reads the Di2 private ANT channels, my recollection was that this data is encrypted, but I could be wrong there. Either way, it does require a license to use it; which is why Shimano was able to pull support from the Karoo in the first place. If I had a Karoo 2, I would get this while it’s hot, and download a copy of the repository just in case it went off-line. But, that said, now that someone has done the heavy lifting any efforts by Shimano to play wack-a-mole will likely just lead to a Streisand effect. The instructions are fairly clear on the repository, but if you want a bit more detail around it, DCR has a good write-up on the installation process.