Bootloader jump to application

The code

Embedded C for Cortex-M. It compiles. There are 3 real bugs in it: the kind that pass a bench test and fail in the field.

void jump_to_app(void)
{
    uint32_t sp    = *(uint32_t *)APP_BASE;
    uint32_t reset = *(uint32_t *)(APP_BASE + 4);
    if (reset == 0xFFFFFFFF) return;

    void (*app)(void) = (void (*)(void))reset;
    __set_MSP(sp);
    app();
}

What an interviewer expects

• Point to each line you'd stop in a code review.
• Say what actually breaks: the failure mode, not just the rule it violates.
• Fix it, then defend the fix when asked the follow-up.

The bugs, reference fixes and the follow-up question are in the practice app, after you've tried it.

Companies that test this

Matched on the skills each company's embedded roles emphasise.

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