A modified bit-flipping (BF) decoding algorithm is proposed for hard-decoding of generalized low- density parity-check codes over binary channels. This approach introduces an extra bit between the variable nodes and constraint nodes representing the decision reliability of each node. The local decoding failure is also analyzed to provide a reasonable treatment for the most of its causes. The approach is not in the direction of constructing codes with minimum trapping sets, but to reduce their effect in the decoder at a cost of little increase in the resources. The algorithm, which is called two-side state-aided BF, is shown by simulations to outperform previous BF algorithms in terms of error performance.