We use the Plotkin (u, u+v)-construction for general Reed-Muller codes (m,r) and relegate decoding to the two constituent RM codes. First, we use the better protected code (m-l,r-1) to find a sub-block v, Then we proceed with the block u from the code (m-l,r), We repeat this recursion on both halves and recalculate the reliabilities of the received symbols. In the end, we perform ML decoding on the biorthogonal codes.