Is there a chatty print that could show what the supported voltages, etc are? I wonder if the kevin charger only does 5 and 20v or something

That charger does support 9V (actually it's the reason I tried it instead of zinger) but I don't think it's relevant to this issue. In this case, the charger doesn't turn on VBUS when attached (eg. does not transition to AttachWait.SRC), probably because it sees Ra voltage on CC, rather than Rd.

I see similar behavior from a pluggable dock / charger that I have, but zinger and an Apple OEM charger both work fine.

I'm pretty sure that I used this charger a number of times when I was working with servo_v4.  I just tested again using TOT FW on my servo_v4.

> C0 st2
C0 st3
C0 st6
Req C0 [2] 9000mV 3000mA
C0 st7
C0 st8
C0 st9