Cartridge attempts to write to ROM locations:

write 6001: 02
write 6000: 06
write 7c11: 40
write 7c10: 41
write 7c11: 01
write 7c10: db
write 7c13: 02
write 7c12: 14
write 7c13: 00
write 7c12: 7d
write 7c15: 3f
write 7c14: 00
write 7c15: 00
write 7c14: db
write 7c17: e1
write 7c16: 00
write 7c17: 00
write 7c16: 06
write 6001: 02
write 6000: 00

Obviously it expects RAM to be mapped at 7c00-7fff. Maybe the access to 6000 is relevant to activate the RAM. 
