[Renate]

I'm pretty happy with things as they are now. I've done a bunch of work on fixing the USB connection so that Onyx can't screw it up. It's always insisting on enabling MTP. My solution won't appeal to many. I just want my rooted ADB.

For those who want to mod their system without using Magisk, the information above is correct, disable verify on /vendor, disable verify on /system, disable error correction on both. To modify DTBs (without "round-tripping" them through dtc disassemble, dtc assemble) you can use my latest released dtbview.exe (in the sig). To extract/replace the dtb in images you can use imgutil.exe

Just extract, dump, hex edit, replace:

C:\>imgutil /x boot.img dtb
C:\>dtbview dtb > dtb.lst
C:\>whatever-hexedit dtb
C:\>imgutil /r boot.img dtb

041b40              vendor {
041b4c                 compatible = "android,vendor";
041b68                 dev = "/dev/block/platform/soc/c0c4000.sdhci/by-name/vendor";
041bac                 type = "ext4";
041bc0                 mnt_flags = "ro,barrier=1,discard";
041be4                 fsmgr_flags = "wait,verify";
041bfc                 status = "ok";
041c0c              }

Then (in this case) look a bit past 41be4 for the comma in "wait,verify" and change it to a null character.

Edit: You can blank the last bit of a partition easily (and without arithmetic):

For systems with eMMC (i.e. 8 x 512 blocks):

C:\>edl /e /pvendor /s-8
C:\>edl /e /psystem /s-8

For systems with UFS (i.e. 1 x 4096 block):

C:\>edl /e /u /pvendor /s-1
C:\>edl /e /u /psystem /s-1