No there is no other solution.
Basically overwriting or updating involves erase and then writing.It is because of the nature of flash devices. In flash you can not transition from 0 to 1. It is always 1 to 0. So when you want to overwrite, you need you will make all the locations as 1 and then make them zero where ever it is necessary. Since erase is involved, the lowest section of flash you can erase is sector. It is not possible to erase individual pages.