Question concerning the Flail of Age +5

So it is right that upgrading the flail from +4 to +5 give to it the free action status.

I guess this can be a problem if you want to haste your character.

But concerning the boots of speed or items that can be applied after you hold the flail in your hand : do they prevent the character to be hasted or gain the advantage of more APR ?

If so, I guess I'll have to rely on Mace of the stars +5 or Hammer of Runes +5 (or perhaps even Flail of the Ages +4).

Thanks for your answers.