FYI...How I Fixed My Own Post v19.1 Problem

Help and Support Raspberry Pi
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I’m running two Raspberry Pi, one a 3B in the bedroom and a 3B+ in the living room, both on auto HDMI switchers, and both ran fine on the Nov 2020 update. Updated both to the Aug 2021 update, and both on first reboot went no signal. They both were up and on the wifi, but nothing coming out of HDMI, and tvservice reported nothing connected.

What finally fixed it was:

  1. Connecting the RPis directly to the TVs HDMIs
  2. Power up the RPis
  3. Once up connect via PuTTY and login
  4. Run “tvservice -s” to see if the RPi is detecting your TV
  5. If so, run “sudo tvservice -d /boot/edid.dat” to create an EDID file from your TV
  6. Run “sudo nano /boot/config.txt” to open up the boot config file
  7. Add at the bottom of the file:
    hdmi_edid_file=1
    hdmi_force_hotplug=1
  8. Save and exit nano
  9. Run “sudo nano /boot/config-user.txt” to open up the boot user config file
  10. Add at the bottom of the file:
    hdmi_edid_file=1
    hdmi_force_hotplug=1
  11. Save and exit nano
  12. Reboot the RPi
  13. Now it’s running off the EDID file

Shutdown the RPi, put your HDMI cabling back through the auto switcher, and it should work fine again, at least my two are. Your mileage may vary.

  • Steps 9 to 11 were added from grahamh’s suggestion so the EDID mod will survive an update. Thank you, grahamh. :+1:
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All good, except add those lines to /boot/config-user.txt to avoid losing them on an update.

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