I'm not sure if this is informational, or if you're still experiencing this issue since it looks like you have done a lot of research already but I will fill in the blanks here. I actually have this on my list to contribute to Troubleshooting content here on iFixit. But it does not occur as often as it used to since this generally occurs exclusively on T1 based models (from 2016/17).
BridgeOS not only drives the Touchbar, BridgeOS is driven by the T1 chip and has hands in many of the hardware functions that T1 controls.
As such, any of the components caught up in BridgeOS can be at fault. Most commonly this issue is related to a faulty touchbar, but it can also be related to any number of components. The best way to troubleshoot honestly is just to open it up and disconnect the touchbar and try to boot that way.
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For reference, since there isn't a touch bar replacement guide on iFixit, here's the location of those connected. be sure to [link|https://www.ifixit.com/Guide/MacBook+Pro+15-Inch+Touch+Bar+Late+2016+Battery+Disconnection/119438|Disconnect the battery first|new_window=true]. This model usually boots without the battery connected just on power from the charger, but you can reconnect for your test if you like. Red is for the touch part, orange for display. Disconnect both for your test and see if you get a proper boot to your login screen.
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For reference, since there isn't a touch bar replacement guide on iFixit, here's the location of those connectors for the Touch Bar. Be sure to [guide|119438|Disconnect the battery first|new_window=true]. This model usually boots without the battery connected just on power from the charger, but you can reconnect for your test if you like. Red is for the touch part, orange for display. Disconnect both for your test and see if you get a proper boot to your login screen.
I'm not sure if this is informational, or if you're still experiencing this issue since it looks like you have done a lot of research already but I will fill in the blanks here. I actually have this on my list to contribute to Troubleshooting content here on iFixit. But it does not occur as often as it used to since this generally occurs exclusively on T1 based models (from 2016/17).
BridgeOS not only drives the Touchbar, BridgeOS is driven by the T1 chip and has hands in many of the hardware functions that T1 controls.
As such, any of the components caught up in BridgeOS can be at fault. Most commonly this issue is related to a faulty touchbar, but it can also be related to any number of components. The best way to troubleshoot honestly is just to open it up and disconnect the touchbar and try to boot that way.
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For reference, since there isn't a touch bar replacement guide on iFixit, here's the location of those connected. be sure to [link|https://www.ifixit.com/Guide/MacBook+Pro+15-Inch+Touch+Bar+Late+2016+Battery+Disconnection/119438|Disconnect the battery first|new_window=true]. This model usually boots without the battery connected just on power from the charger, but you can reconnect for your test if you like. Red is for the touch part, orange for display. Disconnect both for your test and see if you get a proper boot to your login screen.
I'm not sure if this is informational, or if you're still experiencing this issue since it looks like you have done a lot of research already but I will fill in the blanks here. I actually have this on my list to contribute to Troubleshooting content here on iFixit. But it does not occur as often as it used to since this generally occurs exclusively on T1 based models (from 2016/17).
BridgeOS not only drives the Touchbar, BridgeOS is driven by the T1 chip and has hands in many of the hardware functions that T1 controls.
As such, any of the components caught up in BridgeOS can be at fault. Most commonly this issue is related to a faulty touchbar, but it can also be related to any number of components. The best way to troubleshoot honestly is just to open it up and disconnect the touchbar and try to boot that way.