The previous location was the return from the first ets_printf call
that prints ROM sign-on message. Since the main function was patched
in ECO3, the new address no longer works — there is no instruction at
0x40007901 in ECO3 ROM. This could be solved by setting two
breakpoints (one would work for ECO <=2, the other for ECO3), but we
would need to remove the unused breakpoint later.
Fix this by setting the breakpoint at ets_printf. This means that when
debugging a loadable ELF the ROM sign-on message will no longer be
shown, but this doesn't seem to be an issue.
InstrFetchProhibited usually occurs because of a jump to an invalid
pointer. In this case, PC in the exception frame is the address of
the jump destination. 'esp_ptr_executable' check in print_backtrace
function recognizes the first frame as invalid, and the backtrace is
interrupted. This prevents the user from finding the location where
the invalid pointer is dereferenced.
Bypass the 'esp_ptr_executable' check if the exception cause is
InstrFetchProhibited. Update the test case to no longer ignore this
issue.
