[Google Pixel 2 XL Questions & Answers] Jofthesands:
Yeah, I just tried that. I downloaded the 8.1 image and flashed using the flash-all.bat. Below I have the output from the terminal.

E:\Downloads\taimen-opm1.171019.011-factory-2df1c1cb\taimen-opm1.171019.011>flash-all.bat
target reported max download size of 536870912 bytes
sending 'bootloader_a' (36344 KB)...
OKAY [ 0.769s]
writing 'bootloader_a'...
OKAY [ 0.230s]
finished. total time: 1.002s
rebooting into bootloader...
OKAY [ 0.001s]
finished. total time: 0.001s
target reported max download size of 536870912 bytes
sending 'radio_a' (60428 KB)...
OKAY [ 1.277s]
writing 'radio_a'...
OKAY [ 0.844s]
finished. total time: 2.123s
rebooting into bootloader...
OKAY [ 0.001s]
finished. total time: 0.001s
extracting android-info.txt (0 MB) to RAM...
extracting boot.img (40 MB) to disk... took 0.160s
target reported max download size of 536870912 bytes
archive does not contain 'boot.sig'
archive does not contain 'boot_other.img'
extracting dtbo.img (8 MB) to disk... took 0.023s
archive does not contain 'dtbo.sig'
archive does not contain 'dt.img'
archive does not contain 'recovery.img'
extracting system.img (1936 MB) to disk... took 8.534s
archive does not contain 'system.sig'
extracting system_other.img (568 MB) to disk... took 3.011s
archive does not contain 'system.sig'
extracting vbmeta.img (0 MB) to disk... took -0.000s
archive does not contain 'vbmeta.sig'
extracting vendor.img (349 MB) to disk... took 1.823s
archive does not contain 'vendor.sig'
archive does not contain 'vendor_other.img'
wiping userdata...
mke2fs 1.43.3 (04-Sep-2016)
Creating filesystem with 29518843 4k blocks and 7380992 inodes
Filesystem UUID: 4b8c28b4-e04f-11e7-9be1-e19bdc4c5f9d
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872

Allocating group tables: done
Writing inode tables: done
Creating journal (131072 blocks): done
Writing superblocks and filesystem accounting information: done

--------------------------------------------
Bootloader Version...: TMZ12a
Baseband Version.....: g8998-00164-1710262031
Serial Number........:
--------------------------------------------
checking product...
OKAY [ 0.001s]
checking version-bootloader...
OKAY [ 0.001s]
checking version-baseband...
OKAY [ 0.002s]
sending 'boot_a' (40960 KB)...
OKAY [ 0.865s]
writing 'boot_a'...
OKAY [ 0.554s]
sending 'dtbo_a' (8192 KB)...
OKAY [ 0.174s]
writing 'dtbo_a'...
OKAY [ 0.105s]
erasing 'system_a'...
OKAY [ 0.050s]
sending sparse 'system_a' 1/4 (524284 KB)...
OKAY [ 11.581s]
writing 'system_a' 1/4...
OKAY [ 2.212s]
sending sparse 'system_a' 2/4 (524284 KB)...
OKAY [ 11.559s]
writing 'system_a' 2/4...
OKAY [ 2.220s]
sending sparse 'system_a' 3/4 (524284 KB)...
OKAY [ 11.579s]
writing 'system_a' 3/4...
OKAY [ 2.212s]
sending sparse 'system_a' 4/4 (410112 KB)...
OKAY [ 9.067s]
writing 'system_a' 4/4...
OKAY [ 1.724s]
erasing 'system_b'...
OKAY [ 0.039s]
sending sparse 'system_b' 1/2 (524284 KB)...
OKAY [ 11.477s]
writing 'system_b' 1/2...
OKAY [ 2.207s]
sending sparse 'system_b' 2/2 (57588 KB)...
OKAY [ 1.262s]
writing 'system_b' 2/2...
OKAY [ 0.247s]
sending 'vbmeta_a' (4 KB)...
OKAY [ 0.004s]
writing 'vbmeta_a'...
OKAY [ 0.004s]
erasing 'vendor_a'...
OKAY [ 0.017s]
sending 'vendor_a' (357904 KB)...
OKAY [ 7.623s]
writing 'vendor_a'...
OKAY [ 1.508s]
Setting current slot to 'a'...
OKAY [ 0.013s]
erasing 'userdata'...
OKAY [ 0.813s]
sending 'userdata' (5341 KB)...
OKAY [ 0.115s]
writing 'userdata'...
OKAY [ 0.046s]
rebooting...

finished. total time: 79.315s
Press any key to exit...