True firmware downgrading is only possible because the PS4 motherboard keeps two copies of firmware: an and an inactive slot (the previous version you were on).
A: No. Sony only allows updating to newer versions via recovery. Attempting to flash an older PUP results in error code SU-30746-0 – “The update file is old.” Ps4 Tool Downgrade V1.00 Exe Download
to trick the console into fetching the initial game package (v1.00). No Jailbreak Required: True firmware downgrading is only possible because the