just replaced my usb image jun 1.02a with jun 1.02b (had to repair with synology assistant after first boot, took a few seconds, boot after this was ok) and then updated from 6.1.1 u4 to 6.1.2, no problems (as expected, the kernel/drivers are still the same, the problem that rhe drivers in /lib/modules/update are not loaded should be fixed with 1.02b - seems to work for me)