For the still high NOx emissions and a high hopper's thermal fatigue risk in a 600-MWe low-NOx down-fired furnace, a staged arch-firing framework (SAF) is developed as a solution to replace its original deep-air-staging low-NOx art. SAF strategies in resolving these problems include (i) lowering the primary-burner coal/air fluxes and positioning hopper air to shrink the flame penetration and strengthen further air staging and (ii) additionally introducing the primary-burner flue gas recirculation (FGR) and fuel reburning. For a SAF down-fired furnace first using the primary-burner FGR as firing the hard-to-burn anthracite, affirming its availability and evaluating the primary-burner FGR ratio effect on the potentially improved low-NOx combustion and hopper's overheating environment are crucial to the furnace's environmental and safe operations. Accordingly, detailed real-furnace measurements plus simulation are first performed in the original furnace and thereafter, the retrofitted furnace with SAF is evaluated under FGR ratios of 0%, 10%, 12.5%, 15%, and 17.5%. In comparison to the original art, SAF develops a shortened but more effective flame penetration, improves combustion intensity, lengthens the overfire air penetration, and inhibits fuel-NO. The fuel-lean mixture roles first combustion behaviors and then fuel reburning on NO reduction in the fuel-reburning zone. Increasing the FGR ratio drops NOx emissions while weakens burnout. In balancing NOx emissions and burnout, a shallow FGR 12.5% presents the optimal low-NOx merit with NOx emissions lowered to about 600 mg/m3 (6% O2) plus a high burnout. In replacing the original art by the SAF, a further 33.3% NOx reduction plus a high burnout is obtained and the hopper's thermal fatigue risk is eliminated due to its sharp temperature reduction by 400 K.