I've tested latest above values by StabilityTester running 100 times, this gives few errors for 1488 and 1640 MHz.
After increase voltage by 10 for both, StabilityTester run 100 times without error.
I've made PR to master with this.
Ubuntu Bionic, crash on linux-image-dev-sunxi64 5.88.190602, 5.88.190603 and 5.88.190604 (all kernel 5.1.6?)
Last worked was 5.88.190601 (kernel 5.1.5)
Debug log before crashing (full log in attachment):
[ OK ] Reached target Network (Pre).
Starting pNFS block layout mapping daemon...
Starting Create Static Device Nodes in /dev...
Starting Apply Kernel Variables...
Mounting Kernel Configuration File System...
[ OK ] Started pNFS block layout mapping daemon.
[ OK ] Started Create Static Device Nodes in /dev.
[ OK ] Started udev Coldplug all Devices.
[ OK ] Started Apply Kernel Variables.
[ OK ] Mounted Kernel Configuration File System.
Starting udev Kernel Device Manager...
[ OK ] Started Monitoring of LVM2 mirrors,�…sing dmeventd or progress pollin .
[ OK ] Reached target Local File Systems (Pre).
[ OK ] Started udev Kernel Device Manager.
[ 10.523607] Unable to handle kernel paging request at virtual address ffff00c