9370 - dmesg shows "Could not start ICM firmware"

HI,

I have a XPS 13 9370, thunderbolt always shutdowns during startup. dmesg tells me:

[ 7.550153] thunderbolt 0000:05:00.0: enabling device (0000 -> 0002)
[ 7.550644] thunderbolt 0000:05:00.0: NHI initialized, starting thunderbolt
[ 7.550647] thunderbolt 0000:05:00.0: allocating TX ring 0 of size 10
[ 7.550668] thunderbolt 0000:05:00.0: allocating RX ring 0 of size 10
[ 7.550691] thunderbolt 0000:05:00.0: control channel created
[ 7.550692] thunderbolt 0000:05:00.0: control channel starting...
[ 7.550693] thunderbolt 0000:05:00.0: starting TX ring 0
[ 7.550712] thunderbolt 0000:05:00.0: enabling interrupt at register 0x38200 bit 0 (0x0 -> 0x1)
[ 7.550713] thunderbolt 0000:05:00.0: starting RX ring 0
[ 7.550729] thunderbolt 0000:05:00.0: enabling interrupt at register 0x38200 bit 12 (0x1 -> 0x1001)
[ 7.550742] thunderbolt 0000:05:00.0: starting ICM firmware
[ 7.550743] thunderbolt 0000:05:00.0: could not start ICM firmware
[ 7.550746] thunderbolt 0000:05:00.0: stopping RX ring 0
[ 7.550763] thunderbolt 0000:05:00.0: disabling interrupt at register 0x38200 bit 12 (0x1001 -> 0x1)
[ 7.550772] thunderbolt 0000:05:00.0: stopping TX ring 0
[ 7.550788] thunderbolt 0000:05:00.0: disabling interrupt at register 0x38200 bit 0 (0x1 -> 0x0)
[ 7.550792] thunderbolt 0000:05:00.0: control channel stopped
[ 7.550803] thunderbolt 0000:05:00.0: freeing RX ring 0
[ 7.550812] thunderbolt 0000:05:00.0: freeing TX ring 0
[ 7.550817] thunderbolt 0000:05:00.0: shutdown

My DA200 does not work. I am not sure if it is related, but I suspect that it is.

I am running:  4.15.0-111-generic #112-Ubuntu SMP Thu Jul 9 20:32:34 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

Ubuntu is 18.04.

Any clues would be very helpful (certainly more helpful than Dell's "Pro Support").

Thanks,

-jon