The Prophet ﷺ entered Mecca with his banner white.
أخبرنا إسحق بن إبراهيم قال أنبأنا يحيى بن آدم قال حدثنا شريك عن عمار الدهني عن أبي الزبير
أن النبي ﷺ دخل مكة ولواؤه أبيض
Sourcing, hasan. Reported by Abu Dawud in jihad, chapter on banners and standards, hadith: 2592, and Tirmidhi, jihad, chapter on what has been said about standards, hadith: 1679, and Ibn Majah, jihad, chapter on banners and standards, hadith: 2817, from the hadith of Yahya bin Adam, through him, and it is also in Kubra, hadith: 3849. Tirmidhi said, "Gharib." Hakim graded it sahih according to the criterion of Muslim, 2/104, 105. It has a hasan corroborating witness in Ibn Majah, hadith: 2818, and elsewhere.