I am not complaining about instability, that red herring was introduced by others. ,
:~ $ sudo rpi-eeprom-update
CURRENT: Fri 17 Jan 17:37:11 UTC 2020 (1579282631)
LATEST: Fri 17 Jan 17:37:11 UTC 2020 (1579282631)
With arm_freq=2000 I can no longer cold boot but I can warm reboot. So I thought the latest firmware has reduced my potential overclock.
With arm_freq=1980 I could cold boot and warm reboot.
After some thought I decided that the difference was so marginal I would have expected a "grey area" so I upped the frequency.
With arm_freq=2020 I could cold boot and warm reboot. so It is not the silicon. I thought I wondered if....
With arm_freq=2001 I could both cold and warm reboot so it is not the silicon or DVFS firmware in itself. I was just asking if anyone could give an explanation.
By the way I get the same behaviour with Gentoo64 with the same Bootloader but that is still running 24 Sept firmware. I can not find out how to update the vcgencmd version firmware in Gentoo64 which is still in /boot not eeprom.
Perhaps I should say that the cold boot hangs immediately after the the screen where you can press Shift if an overclock fails. I still get a resolution change reported by the TV being used as a monitor but no boot messages on the screen. I am using verbose for boot messages.