Another "No Bootable Device" Problem

Hey, Guys. I know a lot of people have had this problem in the past, but I just can't figure it out and I've been at it all day. I have used the live USB to check and uncheck the boot flag several times, which several people recommended, with no success. Any other ideas? I'll paste my partition information down below if that helps.

This is the first dual boot I have done, so I could be missing something that I'm not aware of. I also tried uninstalling and reinstalling several times, selecting different options based on what I read online, without much success. Thanks guys! I hope someone can help. I know another person having this problem went unanswered.

*** Report for internal hard disk ***

Current GPT partition table:
# Start LBA End LBA Type
1 40 409639 EFI System (FAT)
2 409640 188390023 Mac OS X HFS+
3 188390024 189659559 Mac OS X Boot
4 234958848 236976127 Linux Swap
5 189661184 189663231 GRUB2 BIOS Boot
6 189663232 234958847 EFI System (FAT)

Current MBR partition table:
# A Start LBA End LBA Type
1 1 236978175 ee EFI Protective

MBR contents:
Boot Code: GRUB

Partition at LBA 40:
Boot Code: None (Non-system disk message)
File System: FAT32
Listed in GPT as partition 1, type EFI System (FAT)

Partition at LBA 409640:
Boot Code: None
File System: HFS Extended (HFS+)
Listed in GPT as partition 2, type Mac OS X HFS+

Partition at LBA 188390024:
Boot Code: None
File System: HFS Extended (HFS+)
Listed in GPT as partition 3, type Mac OS X Boot

Partition at LBA 234958848:
Boot Code: None
File System: Unknown
Listed in GPT as partition 4, type Linux Swap

Partition at LBA 189661184:
Boot Code: None
File System: Unknown
Listed in GPT as partition 5, type GRUB2 BIOS Boot

Partition at LBA 189663232:
Boot Code: None
File System: ext4
Listed in GPT as partition 6, type EFI System (FAT)