Normal screw drivers won't work on the screws used on the blocks. Go to your hardware store, take the block with you, and get a screw driver or bits that fits the bolts. Or perhaps you have one laying around...
Should be either
or
. Don't remember if it was hex or torx again - perhaps something else also?.... Anyways, get one that fits nicely or else it's easy to mess up the screw heads.
With the right screw drive or bits type you should be able to open the block.
Should be either


With the right screw drive or bits type you should be able to open the block.