To be more precise, the problem occurs after running oem-config-prepare and rebooting. So, this is probably the same problem as #62648.
Also, higher on the console, there is more interesting information about the error:
File "/usr/sbin/oem-config-dm" line 47 in run (root_width, root_height) = root.get_size()
AttributeError: 'NoneType' object has no attribute 'get_size'
To be more precise, the problem occurs after running oem-config-prepare and rebooting. So, this is probably the same problem as #62648.
Also, higher on the console, there is more interesting information about the error:
File "/usr/sbin/ oem-config- dm" line 47 in run (root_width, root_height) = root.get_size()
AttributeError: 'NoneType' object has no attribute 'get_size'