Credit to torcher and Zapper215 and thier guide on the TOP page

Unpacking
1. Select "File -> Open"

2. Navigate to your FO4 Data folder and open a vanilla texture.ba2 file(such as "Fallout4 - Textures1.ba2")

3. Once Archive2 has loaded the contents of the .ba2 file, select "Archive ->  Extract All To

4. Extract the contents to folder "1" inside the "working" folder



Repacking
1. Select "File -> New" select "DDS" as the format and leave everything default and select "OK"

2. Select "Archive >Add Folder..."

3. Navigate inside folder "1" and select the "Textures" folder

4. Select "File -> Save As..." and save over the original .ba2's name(such as Fallout4 - Textures1.ba2)