[Google Pixel 2 XL ROMs, Kernels, Recoveries, & Oth] GROOVYJOSHCLARK:
*** DO NOT USE OPENGAPPS with this ROM, use MindTheGapps*** I find that OpenGapps is to new for this ROM, IDK why, but every flavor of OpenGapps I tired, they all failed. MindTheGapps is older and works perfectly with this ROM then self-updates the Google framework in the background once its online

Follow my steps and you wont go wrong, trust me, I had a zillion issues with CR and my device (in fact, I had issues with almost every ROM until I sorted out the proper steps). Here is a summary:

I backup ALL TXT/MMS to XML using SMS Backup & Restore by SyncTech Pty Ltd, then I COPY THE ENTIRE internal SD to my PC, so I can format /data and remove encryption and forced encryption later on. BEFORE proceeding, backup ALL TXT/MMS to internal SD (anywhere you choose but its easiest to store at the root of internal storage), then

COPY the entire SD (internal storage) to your PC

. We will then use this once its up and running afterwards to restore everything back to the way it was (under the new OS):

Assuming you saved everything from internal storage, I then ALWAYS fastboot --set-active=a then use the flashall.bat from 9-PQ2A.190405.003 (April 2019 full firmware), WITH THE -W left intact so it wipes and restores all partitions back to stock/default. I then run the process on both slots (set-active=b). Right before it completes the first slot process, I grab the reboot at the last step (right after the VENDORs) and enter fastboot

BEFORE

it boots. After BOTH slots are freshly wiped and restored with the FULL firmware (April) I let it boot into the system. Once this is done, and I have cleanly flashed BOTH partitions with the April full firmware (and ran through the setup without selecting or setting anything), I then OTA the 9.0.0-PQ3A.190801.002 in TWRP (which is the required firmware level for this ROM), but by OTA and not using the FULL flash, I keep encryption sound.

Do the OTA update ONLY AFTER you boot into the April FULL version at least once, then go through the setup but do not set anything, no pins, no gmail, skip EVERYTHING then shut down and reboot into TWRP.

Once its cleaned, I move on to the ROM install:

Fastboot into TWRP recovery (from PC)

Swipe to Factory Reset

FORMAT /data (assuming you copied everything as you will lose the internal storage at this step)

By formatting /data you are cleaning the storage from encryption, not everyone will do this step, its kind of redundant but OCD so I always do it as a pre-caution

Swipe to Factory Reset again (I like to do it twice as I have OCD)

adb push twrp-pixel2-installer-taimen-3.3.0-0.zip /sdcard/

adb push CARBON-CR-7.0-OPAL-RELEASE-taimen-20200122-0821.zip /sdcard/

adb push MindTheGapps-9.0.0-arm64-20190615_031441.zip /sdcard/

adb push Magisk-v20.3.zip /sdcard/

You need t push these files because we formatted /data, NOTE, once you switch slots to install GAPPs, you may need to push them again.

Flash the latest TWRP installer

Flash the CR ROM

Flash the latest TWRP installer (I do this a second time just to ensure it installed to both slots after the OS)

Reboot to recovery in TWRP (this will reboot you into the other slot and use the installed into the device TWRP, not fastboot TWRP)

Flash the latest MindTheGapps (MindTheGapps-9.0.0-arm64-20190615)

Flash Magisk (to bypass forced encryption)

Reboot to system

Done, copy the entire storage back from PC, I then compare the internal storage and my PC to ensure nothing was missed, then I setup my apps, and restore my TXT/MMS. I airplane mode to ensure no messages are missed during the recovery.

Let me know if you have trouble or questions but I also have this more detailed throughout the other Pixel 2 XL ROM forums so if you search them, you will find the step by step in more detail.