Flare frequency distribution for K2 and M2 data. The FFD for TRAPPIST-1 is updated by our flares indicated in orange. The black points are adopted from (Paudel et al. 2018). The best fit to the power law is chosen from 2500 MC trials, here only 100 random samples are shown to mark the uncertainty of the model. Also overplotted are the abiogenesis zone in green (Rimmer et al. 2018; Günther et al. 2020) and the ozone-depletion zone in yellow (Tilley et al. 2019; Günther et al. 2020) for TRAPPIST-1.