If you wrote an update of ~1.7 GB to LUN 0 then you trashed everything up to super and about half of super (4 GB). We may have gotten super fixed (we don't know).
Code:
LUN # Name My Go6
─── ── ────────── ─────────
0 1 ssd zero
0 2 persist ext4
0 3 misc zero
0 4 keystore zero
0 5 frp 40 bytes
0 6 super
So the persist and the frp could be a problem. You should probably zero out all five. The random data can't help.
Code:
edl /u0 /f /p1
edl /u0 /f /p2
edl /u0 /f /p3
edl /u0 /f /p4
edl /u0 /f /p5
You can double check the 4 logical partitions in super.
Code:
edl /u0 /r /psuper super.img
lputil /x /s0 /psystem_a s.img
fc /b s.img from-update-system.img | more
lputil /x /s0 /psystem_ext_a se.img
fc /b se.img from-update-system_ext.img | more
lputil /x /s0 /pproduct_a p.img
fc /b p.img from-update-product.img | more
lputil /x /s0 /pvendor_a v.img
fc /b v.img from-update-vendor.img | more
Has recovery been working? Can you get there?
Edit: I've never had any dealings with the frp, but if Onyx actually enforced that you could be screwed. It's even possible that if you write frp, boot up, then restore the original frp you could be permanently locked out too.
Post-disaster advice: If you had made a full, raw backup you could type a single line, make a coffee and come back to a working device.
Maybe it's time to plead with Onyx. If you have a clear title they can probably reflash it.