02/28/2010. The Firefly F.Mk.I was succeeded by the F.R.Mk.I fighter-reconnaissance aircraft carrying ASH shipping detection radar. Some Firefly F.Mk.Is were brought up to F.R.Mk.I standards as F.Mk.IAs. All production Fireflies prior to the 471st machine were powered by the 1,730 h.p. Griffon IIB, but subsequent Mk.I aircraft received the 1,765 h.p. Griffon XII. A total of 376 F.R.Mk.Is was produced, the last of these being completed on November 23, 1946.