The Prophet ﷺ would pray two rak'ahs before the dawn prayer lightly so much so that I would say: Did he recite Surah al-Fatihah in them.  

كَانَ النَّبِيُّ ﷺ يُخَفِّفُ الرَّكْعَتَيْنِ قَبْلَ صَلاَةِ الْفَجْرِ حَتَّى إِنِّي لأَقُولُ هَلْ قَرَأَ فِيهِمَا بِأُمِّ الْقُرْآنِ  

The Prophet ﷺ would recite in the two (supererogatory) rak'ahs of the dawn prayer: "Say, O unbelievers" [Surat al-Kafiroon:1] and "Say: He is Allah, the one" [Surat al-Ikhlas:1]  

أَنَّ النَّبِيَّ ﷺ قَرَأَ فِي رَكْعَتَىِ الْفَجْرِ { قُلْ يَا أَيُّهَا الْكَافِرُونَ } وَ { قُلْ هُوَ اللَّهُ أَحَدٌ }  

Ziyadah al-Kindi reported on the authority of Bilal that he (Bilal) came to the Messenger of Allah ﷺ to inform him about the dawn prayer. Aisha kept Bilal engaged in a matter which she asked him till the day was bright and it became fairly light. Bilal then stood up and called him to prayer and called him repeatedly. The Messenger of Allah ﷺ did not yet come out. When he came out, he led the people in prayer and he (Bilal) informed him that Aisha had kept him engaged in a matter which she asked him till it became fairly light; hence he became late in reaching him (in time). He (Bilal) said: Messenger of Allah, the dawn became fairly bright. He said: If the dawn became brighter than it is now, I would pray them (the two rak'ahs of the sunnah prayer), offer them well and in a more beautiful manner.  

أَنَّهُ حَدَّثَهُ أَنَّهُ أَتَى رَسُولَ اللَّهِ ﷺ لِيُؤْذِنَهُ بِصَلاَةِ الْغَدَاةِ فَشَغَلَتْ عَائِشَةُ ؓ بِلاَلاً بِأَمْرٍ سَأَلَتْهُ عَنْهُ حَتَّى فَضَحَهُ الصُّبْحُ فَأَصْبَحَ جِدًّا قَالَ فَقَامَ بِلاَلٌ فَآذَنَهُ بِالصَّلاَةِ وَتَابَعَ أَذَانَهُ فَلَمْ يَخْرُجْ رَسُولُ اللَّهِ ﷺ فَلَمَّا خَرَجَ صَلَّى بِالنَّاسِ وَأَخْبَرَهُ أَنَّ عَائِشَةَ شَغَلَتْهُ بِأَمْرٍ سَأَلَتْهُ عَنْهُ حَتَّى أَصْبَحَ جِدًّا وَأَنَّهُ أَبْطَأَ عَلَيْهِ بِالْخُرُوجِ فَقَالَ إِنِّي كُنْتُ رَكَعْتُ رَكْعَتَىِ الْفَجْرِ فَقَالَ يَا رَسُولَ اللَّهِ إِنَّكَ أَصْبَحْتَ جِدًّا قَالَ لَوْ أَصْبَحْتُ أَكْثَرَ مِمَّا أَصْبَحْتُ لَرَكَعْتُهُمَا وَأَحْسَنْتُهُمَا وَأَجْمَلْتُهُمَا  

The Prophet ﷺ said: Do not omit them (the two rak'ahs before the dawn prayer) even if you are driven away by the horses.  

قَالَ رَسُولُ اللَّهِ ﷺ لاَ تَدَعُوهُمَا وَإِنْ طَرَدَتْكُمُ الْخَيْلُ  

The Messenger of Allah ﷺ used to recite in both rak'ahs of the dawn prayer: "Say: We believe in Allah and in the revelation given to us" (3:84) . This is in the first rak'ah and in the second rak'ah (he recited): "We believe in Allah and bear witness that we submit ourself (to Him)." (3:52).  

أَنَّ كَثِيرًا مِمَّا كَانَ يَقْرَأُ رَسُولُ اللَّهِ ﷺ فِي رَكْعَتَىِ الْفَجْرِ بِ { آمَنَّا بِاللَّهِ وَمَا أُنْزِلَ إِلَيْنَا } هَذِهِ الآيَةَ قَالَ هَذِهِ فِي الرَّكْعَةِ الأُولَى وَفِي الرَّكْعَةِ الآخِرَةِ بِ { آمَنَّا بِاللَّهِ وَاشْهَدْ بِأَنَّا مُسْلِمُونَ }  

That he heard the Prophet ﷺ recite in both rak'ahs of the dawn: "Say: We believe in Allah, and in the revelation given to us" (3:84). This is in the first rak'ah. In the second rak'ah he recited this verse: "Our Lord, we have believed in what You have sent down, and we follow the Messenger, so write us down among those who bear witness." or he recited: "Surely, we have sent you with the truth as a bringer of glad tidings, and a warner. And you will not be asked about the inhabitants of the Blazing Fire" (2:119). Al-Darawardi doubted (which of the verse he recited).  

أَنَّهُ سَمِعَ النَّبِيَّ ﷺ يَقْرَأُ فِي رَكْعَتَىِ الْفَجْرِ { قُلْ آمَنَّا بِاللَّهِ وَمَا أُنْزِلَ عَلَيْنَا } فِي الرَّكْعَةِ الأُولَى وَفِي الرَّكْعَةِ الأُخْرَى بِهَذِهِ الآيَةِ { رَبَّنَا آمَنَّا بِمَا أَنْزَلْتَ وَاتَّبَعْنَا الرَّسُولَ فَاكْتُبْنَا مَعَ الشَّاهِدِينَ } أَوْ { إِنَّا أَرْسَلْنَاكَ بِالْحَقِّ بَشِيرًا وَنَذِيرًا وَلاَ تُسْأَلُ عَنْ أَصْحَابِ الْجَحِيمِ } شَكَّ الدَّرَاوَرْدِيُّ