B1.2 fractures involve the surgical neck of the humerus and the lesser tuberosity.
Sequence of repair:
Reduce and fix the lesser tuberosity to the humeral head (thereby converting the 3-part fracture into a 2-part situation)
Reduce the proximal humeral fragment to the shaft and fix it.
If needed, fix the lesser tuberosity with an additional (cannulated) lag screw.