[Google Pixel 3 XL Guides, News, & Discussion] dd805bb:
Yeah this is what I am talking about. You need to flash both partitions same time. Hang on I gotta get script. It is copy and copy.

First flash both slots, then adb both slots the ota. That is the only way I got it to work.

Take the factory image unzip it and unzip the image zip inside the factory image zip all in the same folder.

Grabbing the file now. I am just going to copy and paste it because it is pretty short flash list.

---------- Post added at 04:56 PM ---------- Previous post was at 04:07 PM ----------

Get your factory image, unzip it in a folder name it whatever you like. Also unzip the image.zip inside there all in this same folder. Use extract here. Don't just extract makes a new folder inside.

Take this script. Place it inside the same folder. You need to run it or open it and copy and paste the whole thing into cmd, whatever platform you are using. I use them all, windows, Mac, Ubuntu, works on all that have fastboot. After this runs you be able to get to factory recovery, wipe it. Then go to adb sideload from recovery. Sideload the ota. Wait. Start it and at least get the g logo up and turn back off to recovery and flash the ota again. Turn it back on and balmmo. If you get a boot loop at the very end go into recovery and wipe again. Factory recovery not twrp. Twrp doesn't wipe the Titan chip.

The reason behind flashing the ota twice, during the flashing both slots it won't allow some images to be flashed, fastboot starts not recognizing the partitions. Read it as it flashing. And xda won't let me place the file on here. So I will copy the text in next post. Copy and save it or copy and use it. Doesn't matter this will get you back to working pie.

---------- Post added at 03:57 PM ---------- Previous post was at 03:56 PM ----------

fastboot flash bootloader_a bootloader*.img

fastboot reboot-bootloader

sleep 5

fastboot flash bootloader_b bootloader*.img

fastboot reboot-bootloader

sleep 5

fastboot flash radio_a radio*.img

fastboot reboot-bootloader

sleep 5

fastboot flash radio_b radio*.img

fastboot reboot-bootloader

sleep 5

##Flashing Slot A

fastboot flash abl_a abl.img

fastboot flash aop_a aop.img

fastboot flash boot_a boot.img

fastboot flash cmnlib_a cmnlib.img

fastboot flash cmnlib64_a cmnlib64.img

fastboot flash devcfg_a devcfg.img

fastboot flash dtbo_a dtbo.img

fastboot flash hyp_a hyp.img

fastboot flash keymaster_a keymaster.img

fastboot flash modem_a modem.img

fastboot flash product_a product.img

fastboot flash qupfw_a qupfw.img

fastboot flash tz_a tz.img

fastboot flash vbmeta_a vbmeta.img

fastboot flash vendor_a vendor.img

fastboot flash xbl_a xbl.img

fastboot flash xbl_config_a xbl_config.img

echo "Flashing System A"

fastboot flash system_a system.img

echo "Flashing System B"

fastboot flash system_b system_other.img

##Flashing Slot B

fastboot --set-active=_b

fastboot --set-active=b

fastboot flash abl_b abl.img

fastboot flash aop_b aop.img

fastboot flash boot_b boot.img

fastboot flash cmnlib_b cmnlib.img

fastboot flash cmnlib64_b cmnlib64.img

fastboot flash devcfg_b devcfg.img

fastboot flash dtbo_b dtbo.img

fastboot flash hyp_b hyp.img

fastboot flash keymaster_b keymaster.img

fastboot flash modem_b modem.img

fastboot flash product_b product.img

fastboot flash qupfw_b qupfw.img

fastboot flash tz_b tz.img

fastboot flash vbmeta_b vbmeta.img

fastboot flash vendor_b vendor.img

fastboot flash xbl_b xbl.img

fastboot flash xbl_config_b xbl_config.img