Its a good practice to initialize any used SFR to the desired state, also if this state was equal to the reset state or not.

Then ljmp / lcall 0000h do the job.

Additional this practice avoid any different working on using a boot loader or on debugging.


Peter

P.S.:
To be perfect call a "RETI" routine 2 or 4 times to reset the interrupt logic (4 times on derivates with 4 interrupt levels, e.g. T89C51CC01).