Another nice hike near Bangalore. There are multi-pitch rock climbing routes here.
Parking spot (Bananthimari temple)
The missed trail to the top of BM Betta
As you start from the temple a walk a few hundred steps, there is a small lake1 to your right (not the lake before the temple, next to the road). A few trails are going up to the left here, a few before the lake and a few just after it. Probably on a few 10s of meters until your reach the rock. Marked a section of the trail for help.
To the top the hillock next to BM Betta.
Somewhere near where there is a boulder with a Nama (नामा - a religious symbol) one can reach the top. Can do both, BM Betta top and the hillock next to it. This trail should help.