Originally Posted by someone0
Perhaps, the step between 2 and 3 should be go into the 'system>about' menu, keep tapping 'build number' to enable 'developers option', then go back out and into 'setting>developers option' and turn on 'OEM unlocking'. w/o this option turn on, you can do 'fastboot oem unlock'
And maybe perhaps, before doing anything, why not update the system via OTA first? If the OTA zip is OnePlus official, you should be able to flash it using stock recovery, doesn't it?
side note tip: if you wipe the data partition in TWRP, the default would be ext4, but the OP stock use F2FS. I think it may be wise to change that before wiping the data partition.
Done. Should now default to f2fs on data wipes as well. (redownload, I didn't change the version number)
Yes that is an option.
Originally Posted by ghettopops
So that I understand, separate recovery partition means that I can have both TWRP and Oxygen Recovery installed. Allowing me to get updates and install them through Oxygen Recovery while maintaining a TWRP recovery? Also is it just a matter of booting into them via fastboot?
No, separate recovery partition means you can flash kernels and recoveries separately. It means recovery isn't part of the system boot image, which is an idiotic design of the Pixel phones that is hurting custom development for them. See example:
OnePlus 3T (and every other sane device):
boot partition = system boot image
recovery partition = recovery boot image
result = you can use twrp to flash custom roms! any issues = just try in twrp again!
boot partition = boot image with recovery ramdisk that loads system (???)
boot_a partition = the same thing as boot partition (??? again)
recovery partition = nowhere to be found
result = flash a bad custom rom? say goodbye to twrp!