Several times after a fresh installation of Raspberry Pi OS (FKA Raspbian) the device would end up in a boot loop, displaying the rainbow gradient, sometimes a quick splash screen and then restart again. Most likely a possible fix of the problem with configuration changes would be done in
config.txt file located on the
In this case with a new installation of the most recent official stable build, a new SD Card, and a (essentially) new device which had been successfully run prior to this problem led attention to the monitor. Since each monitor/TV has their own firmware, settings, etc. then an adjustment to the group and/or mode values could do the trick.
Open /boot/config.txt and edit the two lines initially commented out (on a default installation).
$ sudo nano /boot/config.txt
# uncomment to force a HDMI ... hdmi_group=1 hdmi_mode=4
This is all it took for the “monitor” (actually TV) being used (Samsung UN19F4000). Review the information on all HDMI settings within the
config.txt documentation for the Raspberry Pi, and the differences between the models (e.g. some models ignore certain options) so the proper settings become apparent. Here is the information on the
config.txt found on raspberrypi.org.