Not involved with this particular matter. What I would want to see is logs of the behavior of the failing subsystem and details of the failing environment. This may be able to to be reproduced in an environmental testing lab, a systems rig lab, or possibly even in a completely virtual avionics test environment. If stimulating the subsystem with the same environmental input results in the error as experienced on the plane, then a fix can be worked from there. And likewise, a rollback to a previous version could be tested against the same environment.