abb_inth.c: check all interrupt causes, not just one The original code used if - else if - else if etc constructs, thus the first detected interrupt was the only one handled. However, Iota ITSTATREG is a clear-on-read register, thus if we only handle the first detected interrupt and skip checking the others, then the other interrupts will be lost, if more than one interrupt happened to occur in one ABB interrupt handling cycle - a form of rare race condition. Change the code to check all interrupts that were read in this cycle.