Polycrystalline PrBa2Cu4O8 (Pr124) has been prepared at ambient oxygen pressure by nitrite pyrolysis method. Powder x-ray-diffraction patterns show a nearly single R124 phase. Thermogravimetric analysis indicates that its thermal stability is distinct from that of Pr123. Specific heat C has been measured from 0.5 to 40 K, and is very similar to that of Pr123. A maximum of C occurs around 17 K which could be due to a magnetic ordering. Entropy difference ΔS has been calculated from ΔC/T between Pr124 and Y124. The possible origins of ΔS and the related magnetic properties are discussed. Resistivity ρ(T) of Pr124 shows a nearly metallic behavior similar to what was observed in Pr124 made by the O2-HIP technique. The metallic ρ(T) at low temperatures is of interest and will be discussed.