The elimination of such problems is possible if the bubbles are not very large and there are not very many of them. If the scale of the defects is huge, it is best to lay up the installation. First, the bubble must be pierced. By releasing air from it, you can try to iron it with an iron. Naturally, having previously put a sheet of paper. Through these actions, the mastic will have to warm up and glue this part of the linoleum again. It may turn out that there was no mastic in this place at all. Then, through a small incision, it will be necessary to manage a thin object (stick, pencil) to put a little mastic there. Also, if the bubbles are not small, you can not try to smooth this place with an iron, but put a bag of hot sand on it.