Less than a month after Google's official announcement of the Pixel 2 and 2 XL, XDA Senior Recognized Developer Dees_Troy announced alpha support for the popular TWRP recovery for the Pixel 2 and the Pixel 2 XL late Monday night.
A custom recovery, of course, is the first step towards rooting and flashing a custom ROM, though at the moment there are other hurdles that must yet be overcome before custom Oreo ROMs will run on either generation of the Pixel phone lineup.
Also, it is important to note that important functions such as Media Transfer Protocol (MTP) don't work, so you won't be able to transfer files to and from your PC while your phone is in TWRP recovery. In addition, you won't be able to use TWRP to decrypt, backup, or restore your data. Finally, Dees_Troy stated that he doesn't know what will happen if you try to perform a factory reset with the custom recovery on your Pixel 2 or 2 XL, and you'll only be able to use TWRP in a "temp-boot" state.
TWRP ALPHA FOR PIXEL 2TWRP ALPHA FOR PIXEL 2 XL
Dees_Troy recommends that you have the factory images already downloaded and ready to flash in case anything goes wrong while you use this alpha version of TWRP recovery on your second-generation Pixel phones. As with any such modifications, users assume the full risk and responsibility for any potential problems that may occur with the use of TWRP. In fact, I'd recommend waiting until some of the bugs get ironed out. There's not much to flash for the phones yet anyway.