This whole function is only relevant on cores with revision >= 5, otherwise there's no need to do anything, it always succeeds.
The function has a parameter that requests if the PHY should be connected or not.
If the phy should be connected:
Check if coreflagshigh (http://bcm-specs.sipsolutions.net/core_information_registers) contains 0x01, if not fail
- Set PHYConnected to true
- Turn on bit 0x800 in coreflagslow
- Check if coreflagshigh contains 0x02, if not fail
- Set PHYConnected to false
- Turn off bit 0x800 in coreflagslow