rock64 verbose boot hangs

From: Andriy Gapon <avg_at_FreeBSD.org>
Date: Sat, 18 Sep 2021 12:58:00 UTC
Normal boot works every time, but with boot_verbose="YES" it hanged on all 
attempts so far.

Last messages on the console:
cpulist0: <Open Firmware CPU Group> on ofwbus0
cpu0: <Open Firmware CPU> on cpulist0
cpu0: Nominal frequency 600Mhz
cpufreq_dt0: <Generic cpufreq driver> on cpu0
cpufreq_dt0: 408.000 Mhz (950000 uV)
cpufreq_dt0: 600.000 Mhz (950000 uV)
cpufreq_dt0: 816.000 Mhz (1000000 uV)
cpufreq_dt0: 1008.000 Mhz (1100000 uV)
cpufreq_dt0: 1200.000 Mhz (1225000 uV)
cpufreq_dt0: 1296.000 Mhz (1300000 uV)
cpu1: <Open Firmware CPU> on cpulist0
cpu1: Nominal frequency 600Mhz
cpufreq_dt1: <Generic cpufreq driver> on cpu1

The kernel is totally unresponsive after that.

Any suggestions on how to debug this?
Thanks!
-- 
Andriy Gapon