On the Effects of Errors During Boot

We present the results of injecting errors during the boot phase of an embedded real-time system based on the ERC32 space processor. In this phase the hardware is initialized, and the processor executes the boot loader followed by kernel initialization. For this reason most system support is not yet available and traditional fault-injection techniques such as  cannot be used. Thus our study was based in the processor’s IEEE 1149.1 (boundary-scan) infrastructure through which we injected about 5000 double bit-flip errors. The observations show that such system will either crash(25%) or execute correctly(75%), since only 2 errors eventually lead to the output of wrong results. However about 10% of faults originated latent errors dormant in memory. We also provide some suggestions on what can be done to increase robustness during this system state, in which most fault-tolerance techniques are not yet setup.