Today during Fajr jamah while I was saying takbeer-e-tehrima I think that is when the imam said salam. It is possible that I said takbir before the imam said the first mim but I sat down and then stood up with those who had missed rakahs. I thought that I did not get the jamah therefore I need to start the salah again so I stood up and without moving my chest much away from qiblah, said niyyah and takbir again to start my own Fajr.
My confusion is that did my 2nd Fajr 2 fardh start since I did not say salam before saying niyyah as I thought my first salah did not start. Was my 2nd Fajr fardh valid?
If you said takbir tahrima after the first mim of first salam of imam and you are sure about it then your iqtida was not right and you did not join the salah with imam. However, if you stood and offered fardh without turning salam with intention and takbir tahrimah then your Fajr salah was valid.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband