[a3n]

It doesn't matter what group was materially at fault, internal or external. It says "Boeing" on the tin. It's Boeing's responsibility to ensure integrity of all supply inputs, hardware or software.

Disclosure: I was a Boeing employee in the early 90s, and wrote software to control test systems that exercised electronic subsystems. The subsystems were supplied by vendors, and in some cases some of the test hardware too.

Disclaimer: I know nothing.