When using "ORG 7C00h" in a bootloader we indicate that the offsets used in the program shall be relative to linear address 0.
This also means that you are required to initialize the DS segment register to zero in stead of the 07C0h value that you used. Luckily your current bootloader never depends on this mistake and so everything seems OK.
nkeck720
commented
8 years ago
When using "ORG 7C00h" in a bootloader we indicate that the offsets used in the program shall be relative to linear address 0. This also means that you are required to initialize the DS segment register to zero in stead of the 07C0h value that you used. Luckily your current bootloader never depends on this mistake and so everything seems OK.