TS101 reboots with MacBook M2 Pro PD

[nuschpl]

Describe the bug
It cycles through power state 3, then 6 and reboots.

To Reproduce

1. Connect to MacBook M2 Pro PD
2. Observe decvice negotiating then rebooting.
3. Connect with KeyB pressed, get PD Debug state 3, PD Debug state 6.

Expected behavior
Whatever power is provided via USB PD properly negotiate it so the iron will use only supported ones. Ideally when power not sufficient to iron but sufficient for powering up it should display the limitation

Details of your device:

• Device: TS101
• Release: [compiled from git head on 2024 Feb 27]
• Power adapter being used: MacBook M2 Pro Thunderbolt 4 port

[nuschpl]

As a followup - I've attempted to limit artificially maximum power to 15W by modyfing configuration.h . Compiled the firmware and it was working - on 140W capable PD charger it was runing only at 5V max very slowly heating . This is the behaviour I would expect on Macbook but it with same firmwre it still restarts instead - seems like some PD negotiation issue similar to #762 (comment)
I'm eager to debug it further by collecting some logs or compiling custom firmware with some changes , not sure were to start.

[akubak]

@nuschpl I was able to flash mine by using an old Type-C to USB-A phone cable through a hub connected to my laptop, so that no PD info was passed along to confuse the iron.

[nuschpl]

I'm aware that it should be possible but this issue is not about flashing, it's precisely about proper USB PD support