On the authority of Ḥafṣah, from the Messenger of Allah, may Allah bless him and grant him peace, that when the call to the dawn prayer was made, he would pray two short rakʿahs before standing for the prayer. (1)

And it is narrated from Sālim, from Ibn ʿUmar, from Ḥafṣah:

1778 — Isḥāq ibn Ibrāhīm informed us, saying: ʿAbd al-Razzāq informed us, saying: Maʿmar narrated to us, from al-Zuhrī, from Sālim, who said: Ibn ʿUmar (2) said: Ḥafṣah told me that the Messenger of Allah, may Allah bless him and grant him peace, used to pray two rakʿahs before dawn, and that was (3) after dawn had risen. (4)

1779 — al-Ḥusayn ibn ʿĪsā informed us, saying: Sufyān narrated to us, from ʿAmr, from al-Zuhrī, from Sālim, from his father, who said: Ḥafṣah told me that the Messenger of Allah, may Allah bless him and grant him peace, when dawn became clear to him, prayed two rakʿahs. (5)

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(1) A sound ḥadīth, and it is a repetition of ḥadīth (1760) in chain and text.
(2) In (R) and the margin of (H): from his father, who said.
(3) In (R), (M), and (H): and that was.
(4) Its chain is sound. ʿAbd al-Razzāq: he is Ibn Hammām al-Ṣanʿānī, and Maʿmar: he is Ibn Rāshid al-Baṣrī.
It is in the "Muṣannaf of ʿAbd al-Razzāq" (4771) with the wording: when dawn rose, he prayed two light rakʿahs.
Ibn Ḥibbān also transmitted it following (2473) via the path of ʿAbd al-Razzāq, with this chain.
Al-Tirmidhī transmitted it (434) from al-Ḥasan ibn ʿAlī, from ʿAbd al-Razzāq, with it, without mentioning Ḥafṣah, making it a ḥadīth of Ibn ʿUmar, thus making it a mursal of a Companion, and al-Tirmidhī said: a ḥasan ṣaḥīḥ ḥadīth.
See what precedes it and what follows it, and what has passed under number (1761) and the commentary on it.
And it has passed under number (583) via the path of Zayd ibn Muḥammad, from Nāfiʿ, from Ibn ʿUmar, from Ḥafṣah.
(5) Its chain is sound. al-Ḥusayn ibn ʿĪsā: he is Ibn Ḥumrān al-Ṭāʾī, and Sufyān: he is Ibn ʿUyaynah, and ʿAmr: he is Ibn Dīnār.
And it has passed under number (1761).