Enable ADB and/or change USB connection mode on Galaxy S7 w/ broken screen

Question

My Galaxy S7 Edge has a broken screen (totally black, and doesn't respond to touch). However, the phone does turn on and is recognized by Kies 3 and SmartSwitch. I am also able to unlock the phone via thumbprint (sometimes), or via OTG USB keyboard input (always).

The problem is that the USB connection mode is PTP, and I can't see the screen to change it to MTP so that SmartSwitch can retrieve data from the device.

I don't have USB debugging enabled on the device, so I can't change the settings that way.

And since the S6, there's no video output, so I can't buy an MHL+OTG adapter to view the output on a TV and change the settings via mouse.

I've tried booting into recovery mode by holding volume down + power + main button for 30 seconds, but nothing seems to happen. Even if I get into recovery mode, I'm not sure if I can enable ADB, and if that setting would persist after a restart.

I've also called Samsung support, which was useless.

Are there any options for me to either enable ADB, change the USB connection mode, or send video output to another display?

Answer 1

I cannot test this method because my device don't have USB-OTG support. I am not sure if the key sequence is always the same on each phone, this is for android 7.0 nougat

This only works with PIN or password! This only works once when installed the first time! we need to pick up the Google Play notification, make sure you won't disturbed by incoming calls or messages. call it the notification method :)

• download adb platform_tools or scrcpy
• install your phone usb drivers to PC
• remove your SIM card
• turn on your device with internet connection
• wait a while to get all recent incoming notifications
• connect your keyboard with USB-OTG adapter
• open a web browser on PC
• remote install this app to your device Developer Options
• wait ~1-2 minutes until the app is installed to your device
  (after this step you can switch off your WiFi router)

lets (hopefully) select the Google Play notification from lock screen directly with arrow keys. Do this fast within ~5-10 seconds!

• press ↑ arrow up (10 x times)
• press ↓ arrow down
• press Enter
• type your PIN / password
• press Enter

We have successfully unlocked the screen now and opened the app which opened the Developer Settings.

Now lets activate Developer Settings and enable USB-Debugging
do this right after unlocking, if you wait too long your screen becomes locked again

select Developer Settings and confirm dialog 'okay'

• press Space Space
• press → arrow right
• press Space Space

scroll down to usb-debugging (sequence may differ for your device)

• press ↓ arrow down (11 x times)

select USB-Debugging and confirm dialog 'okay'

• press Space Space
• press → arrow right
• press Space Space

If all wents well, now comes the tricky part. You have successful enabled usb-debugging. But you still can not access your phone. Your PC is not authorized!

• open cmd.exe as administator and cd change directory to the folder where adb.exe is installed (platform-tools or scrcpy)
• connect your device with usb cable to PC
• type adb devices you should see 'unauthorized'
• connect your keyboard with USB-OTG adapter
• press Space Space
• type your PIN / password
• press Enter
• press → arrow right
• press Space Space

Congratulations! You have successfully enabled usb-debugging and accepted your PC's RSA-Key