With the >= used let's say you have four RMT inputs, each using 2 channels wide for their receive buffer. This is 4*2 = 8 buffers which is the number of hardware buffers (MAX_CHANNELS). But, for the fourth input the starting buffer will be 6 (this is correct, the buffers used for each input are 0-1, 2-3, 4-5, 6-7). But, 6+2 = 8 which is MAX_CHANNELS. This is valid but the >= would match against it and abort. It is correct to only abort if the value i+j is only greater than MAX_CHANNELS. Thus, a simple one character fix. Delete the equals sign.
7b3c1dfd50