Read the statement by Michael Teeuw here.
Lost resolution after reboot?!?
- 
 Hi there, 
 my MagicMirror worked fine, until I had to rebbot the Pi for some reason.
 After rebooting the resolution is far too low. I use a Samsung Syncmaster 245B+ with FullHD.How can I fix this? Cheers 
 KC
- 
 Hi. Was your display switched off during reboot? I had that with my tv and follow a small tutorial to save my display settings so the pi does not care if the display is on or off during boot 
- 
 No, unfortunately the Monitor was turned on. I think there is sth wrong with the settings in /boot/config.txt 
 But I can’t figure out, how to fix this.
- 
 So, here ist my /boot/config.txt: # For more options and information see # http://www.raspberrypi.org/documentation/configuration/config-txt.md # Some settings may impact device functionality. See link above for details # uncomment if you get no picture on HDMI for a default "safe" mode hdmi_safe=1 # uncomment this if your display has a black border of unused pixels visible # and your display can output without overscan #disable_overscan=1 # uncomment the following to adjust overscan. Use positive numbers if console # goes off screen, and negative if there is too much border #overscan_left=16 #overscan_right=16 #overscan_top=16 #overscan_bottom=16 # uncomment to force a console size. By default it will be display's size minus # overscan. #framebuffer_width=1280 #framebuffer_heiframebuffer_width=1080 #framebuffer_height=1920 #framebuffer_depth=32 #framebuffer_ignore_alpha=1 # uncomment if hdmi display is not detected and composite is being output hdmi_force_hotplug=1 # uncomment to force a specific HDMI mode (this will force VGA) hdmi_group=2 hdmi_mode=69 # uncomment to force a HDMI mode rather than DVI. This can make audio work in # DMT (computer monitor) modes hdmi_drive=1 # uncomment to increase signal to HDMI, if you have interference, blanking, or # no display #config_hdmi_boost=4 # uncomment for composite PAL #sdtv_mode=2 #uncomment to overclock the arm. 700 MHz is the default. #arm_freq=800 # Uncomment some or all of these to enable the optional hardware interfaces #dtparam=i2c_arm=on #dtparam=i2s=on #dtparam=spi=on # Uncomment this to enable the lirc-rpi module #dtoverlay=lirc-rpi # Additional overlays and parameters are documented /boot/overlays/README # Enable audio (loads snd_bcm2835) #dtparam=audio=on display_rotate=3 avoid_warnings=1The Samsung Syncmaster 245plus has a native resolution of 1920x1200@60Hz. 
 I think the hdmi_group an _mode settings are correct, but it still doesn’t work…
 What is wrong?
- 
 /opt/vc/bin/tvservice -s state 0x120006 [DVI DMT (4) RGB full 4:3], 640x480 @ 60.00Hz, progressiveThat is the resolution shown by the Raspi. Slowly I have the feeling like sitting at an Windows-Machine… 
- 
 
- 
 /opt/vc/bin/tvservice -m CEA Group CEA has 2 modes: mode 4: 1280x720 @ 60Hz 16:9, clock:74MHz progressive mode 16: 1920x1080 @ 60Hz 16:9, clock:148MHz progressive /opt/vc/bin/tvservice -m DMT Group DMT has 1 modes: (prefer) mode 4: 640x480 @ 60Hz 4:3, clock:25MHz progressiveThe Mirror worked for mont without any issues… 
- 
 @Kai-Christoph said in Lost resolution after reboot?!?: hdmi_group=2 means “use DMT” 
 hdmi_group=1 would use CEASo I would suggest finding out possible modes in CEA and set these in your config.txt 
- 
 tvservice -d edid Nothing written!I tried this before… 
 edid seems not to work.
- 
 Now I tried this, as mentioned here hdmi_cvt=1920 1200 60 5 0 0 1Nothing happened: The Raspi stucks on 640x480… 

