Please:
- Boot into 3.6.0 and take photographs/a screenshot of exactly what happens
- Using the GRUB menu (following these instructions to display it if you have trouble), boot into 3.5.9
- Follow the first set of instructions here to generate an eos-diagnostic log, and attach it here
- In a Terminal window, run
pkexec eos-rollback(authenticating when prompted) to make your system boot into 3.5.9 by default