Updated to version 3.2.2-0 (20180704).
The latest official 18.104.22.168 can't mount data (tapping the data mount checkbox does nothing; stays unchecked). I formatted it, rebooted, confirmed data was mountable, then booted into AOSP 8.1. Once rebooting back into TWRP it can no longer mount data. Am I missing something?
Edit: Log message is:
Could not mount /data and unable to find crypto footer.
Failed to mount '/data' (Invalid argument)
Yes..you need a PC
What are you talking about? OEM partition doesn't "override" the kernel, nor it's related to it. When you're on stock firmware, OEM partition will hold an EXT4 filesystem containing customization and apps from your operator or your country customization in the case of a carrier free device. When you're using custom ROMs, the OEM partition will hold the ODM image that you need to flash during the installation of the ROM, generally through fastboot flash oem <ODM image> or through TWRP itself on newer versions. Regardless of what is being stored there, TWRP should backup this partition just fine (at least it does on my phone)...
fastboot flash recovery twrp-3.x.x-x-suzu.img fastboot reboot