The PCB has already appointed former players Mushtaq Ahmed and Moin Khan.
The judgement means all decisions taken by Sethi-led Board now stand void.
Najam Sethi said he was in the process of giving the PCB a democratic constitution.
Zaka Ashraf said he will try to correct the wrong things in Pakistan cricket.
Mohsin Khan said he couldn't comprehend logic behind Flower's appointment.
The former Zimbabwe batsman will be joining Waqar Younis's support staff.
Grant Flower is almost being finalised by the PCB for the role.
Sethi has maintained faith in Waqar, Moin and the captain to improve the performances.
Flower has applied for the job but PCB would prefer Inzamam.
Despite living under Andy Flower's shadow, Grant had his fair share of success.