Confirmed, the device is booting again.
Is the 838x target supposed to allow overclocking?
In dmesg this is logged:
[ 0.000000] rtl83xx-clk: initialized, CPU 500 MHz, MEM 300 MHz (8 Bit DDR3), LXB 200 MHz
[ 0.000000] clocksource: MIPS: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041786 ns
[ 0.000000] sched_clock: 32 bits at 100 Hz, resolution 10000000ns, wraps every 21474836475000000ns
[ 0.000000] Calibrating delay loop... 498.89 BogoMIPS (lpj=2494464)
...
[ 0.090000] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
...
[ 0.270000] rtl83xx-clk clock-controller: rate setting enabled, CPU 300-625 MHz, MEM 300-300 MHz, LXB 200-200 MHz, OVERCLOCK AT OWN RISK
However, overclocking is not possible.
root@OpenWrt:/# cat /sys/bus/cpu/devices/cpu0/cpufreq/scaling_available_frequencies
325000 350000 375000 400000 425000 450000 475000 500000
root@OpenWrt:/# echo '625000' > /sys/bus/cpu/devices/cpu0/cpufreq/scaling_setspeed
ash: write error: Invalid argument
Also, when changing clock speeds this message appears in the console. I think it was mentioned somewhere else already.
root@OpenWrt:/# echo 'ondemand' > /sys/bus/cpu/devices/cpu0/cpufreq/scaling_governor
root@OpenWrt:/# [ 393.200000] R4K timer is unstable due to CPU frequency change
Furthermore, wall times are not calculated correctly with changed clocks (known limitation as per PR). Actual processing speed changes in accordance to the reduction in clock speed though. I've tested this via timed ssh.