Business & farm

What Form do the terms "Box 1" and "Box 2a" refer to?

If it's the corresponding boxes on K-1: Box 1 for ordinary income(loss) and Box 2 for Net real estate income(loss), it seems impossible to allocate the carryover loss between them because on Form 8285 Worksheet 6 column (b) from prior year all those losses from multiple previous years are summed up as one number. 

How are we supposed to know how to allocate losses between Box 1 and Box 2a?
What do the "Box 1" and "Box 2a" refer to? It would help to know.