This suggestion looks a little bit more likely as your first try.

But I fear, Philips was watching this and implemented some security logic to avoid this. Maybe writing to ENBOOT take no place if invoked by external code.


Also switching EA may damage always the current code fetch. E.g. on most data sheets it was suggested only, if the state of EA has no effect.

E.g. on an older design we used an OTP derivate, but needed in application programming. Thus I connected an external Flash and this Flash contain the routine to switch EA on and off on an address outside the internal OTP space, so the current (external) code fetch was never affected.


Peter