Grading: The hadith is "sahih", like the previous one, and this chain is "hasan" in corroborating chains and supporting reports because of Yahya bin Abd al-Hamid (al-Himmani); he is weak, but he is taken into consideration in corroborating chains.

Reference / Source: Abd Allah bin Ahmad recorded it in "Fada'il al-Sahabah" (293) and said: "I was informed from Abu Yahya al-Himmani."
Technical note / Defect ('illah): Abd Allah bin Ahmad left the one who informed him (who told him the hadith) unnamed, and the strong likelihood is that he is "Yahya bin Abd al-Hamid", since Abd Allah does narrate from him. He limited himself to the command to follow Abu Bakr and Umar.

Reference / Source: Ahmad (38/23276, 23419), Ibn Majah (97) and al-Tirmidhi (3799 M) recorded it from Waki', and Ibn Majah (97) from Mu'ammal bin Isma'il; both of them via Sufyan al-Thawri > Abd al-Malik bin Umayr > a mawla of Rib'i > Rib'i > Hudhayfah.
Technical note / Defect ('illah): And this mawla (freed slave) of Rib'i is "majhul" (unknown).

Important point: Abd al-Malik bin Umayr's narration from Rib'i bin Hirash is well known, famous and established, and it is used as proof in the two Sahihs and elsewhere. So it is not unlikely that Abd al-Malik heard it both from Rib'i and from his mawla. In that case this narration of Sufyan would be of the type "al-mazid fi muttasil al-asanid" (i.e. an extra intermediary added within a connected chain). And Allah knows best. See the coming narration at (no. 4503).