Can one offer Salah behind an Imam wearing Tameemah (Qur'anic verses wrapped in a piece of cloth on the top of the arm)? I told the Imam and also gave the book stating that Tameemah is SHIRK as per Hadith of Prophet Muhammad Sallallahu Alaihi wa sallam written in musnad Ahmed, but he is saying that some Ulama's allow it. They say that intention should be that Almighty Allah does all things and this Tameemah is only a means (Asbab). And till now he has not removed it. So please reply in the light of Qur'an And Sunnah.Can I form a Jamaat for Salah along with one or two or more people, after I come late to a mosque where Salah is offered by Imam on time? Is it allowed for me to make such a Jamaat when one Jamaat is already over? Reply in the light of Quran and Sunnah.

Praise be to Allah, the Lord of the Worlds; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
This Imam should be reminded that his leading position requires him to show a good example to other Muslims. So he should not do any forbidden things like carrying Tamimah (amulet). But you should pray with him unless he says that he believes that Tamimah is lawful even if it contains things other Qur'an.
If you come to the mosque and find out that you have missed the congregational prayer, there is no harm in your praying in another Jamaa' in the same mosque, some scholars even think that this is better and more appropriate.
Ahmad and Al Tirmizi narrated from Abu Said Al Khudri that the Prophet was once sitting among his companions when a man entered after the prayer was finished. The Prophet said: "Who wants to give charity to this man by praying with him". One of the people present stood up and prayed with this man.
Other scholars believe that it is dislikable to make two Jamaa' in the same mosque for the same prayer, especially if there is an appointed Imam and the mosque is not in a market or a place where there are many people.
Allah knows best.