Just to make sure…you did start counting from 0 hrs after each round of power off & on and checking the kernel dmesg output?
I have UART (serial debug console) disconnected. Have two RJ45 plugged in. DC12V plugged in but powered off.
Maybe I should try with the two RJ45s unplugged…
Of course started from 0 after poweroff and swited off on my dc powercable…but i guess my serial adapter gives enough power to the rtc
Tested with all RJ45 unplugged. Cannot survive 5 hours.
So I think I reached my conclusion. My R4 and possibly production batch 3 & onwards can survive 4hrs+ but not passing 4.5 hrs.
Still very good.