A2337 820-02016 - logic board + what extra hardware required for DFU?

[Sniffy]

Hi,

Here's what I've got:
a2337 logic board (bom variant 639-11766) from late 2020 m1 air
USB-C I/O 821-01658-A ribbon
(no battery, dc-charger, keyboard, touchID, screen, or power button)

WHAT WORKS:
Recovery and fallback recovery
HDMI output
USB mouse/kb input
DFU mode detection on other devices

WHAT DOESN'T WORK:
No bootable volumes detected
Can't get to DFU (boots straight to recovery on power via usb-C) even with SOC_FORCE_DFU pulled to 1.8V via short (per wiki), or to 1.22V via 1kOhm (per schematic).

QUESTIONS:
1. Do I need more parts from an a2337 present to get to DFU?
2. If the board autoboots when power is connected, is there a way to prevent that so that I can get to DFU? Spoofing lid closed with tweezers isn't working.
3. Is USB-C 20V negotiation needed for DFU without a battery, or can it work when the 3217 is in boost mode from 12V?

(btw no password in recovery, can erase etc, but not sure if it's activation locked since I can't connect to a network - still waiting on a usb-c ethernet adapter to debug that... but maybe if it's activation locked then DFU is disabled?)

Tools:
Multimeter
Schematic (ty badcaps)
Brdview (again, thanks to this forum)
2018 macbook USB-C power adapter+cable
idevicerestore on a linux box
AC2 2.12 (oof... can't find 2.13 anywhere) on a macOS 10.15.7 hackintosh
USB-C to HDMI +a few usb-a for keyboard/mouse

[Sniffy]

Re: A2337 820-02016 - logic board + what extra hardware required for DFU?

For those who have a similar problem in the future, debug process looked like:

1. Make sure that the DFU cable isn't the issue: use R1725 to check DFU state (1.2V if true), and swap around cables until it shows in idevicerestore (if you don't have a new mac for AC2 >2.13.0).

2. To actually get to DFU from recovery, I shorted pin30 on JT400 to the adjacent ground pads with tweezers as soon as I shut down from recovery, then applied the jumper for DFU while holding the tweezers in place. I'm sure there is another way that doesn't require this (obviously if you have a working lid sensor or keyboard), but I don't know it.