You have to go to route 2 after you have gotten cut. Then you place the pokemon who knows cut where the small tree is. After you beat the level Prof. Oak should come out and give you flash. I hope I helped!
go past rock tunnel
To navigate through Rock Tunnel
On the map, yes the power plant is by the Pokemon Tower. However, the Power Plant is on the northern side of Rock Tunnel. From the northern entrance of rock tunnel, surf south past the mountain until you find land. The Power Plant is located here.
Rock Tunnel (Uncommon) and Route 10 (Uncommon).
use the move Flash (TM70)
Go to Rock Tunnel at Cerulean City(maybe I spelled it wrong) there would be a boy in there with the yellow hat will teach one of your Pokemon(you have to have a Pokemon that is a rock type)
go there lol yea u do go there but you have to go through rock tunnel
when you get cut teach it to a pokemon in your party and go back and beat route 2 and professor oak will give you flash the go to rock tunnel with a pokemon that know flash and it should light up and the onix will be gone
Go to the pokemon centre at rock tunnel and surf southwards. Rock tunnel is east of cerulean.
In order 2 get to rock tunnel u need 2 have cut.u go 2 the east of cerulean city and use cut at the tree.go beat all the trainers and find the right way.
Get Flash from a guy a route 2 Get Flash from a guy on route 2
it's past mount moon but not past rock tunnel keep going. watch for trainers they can get annoying.when you see water ride on it