Block HP can be set to any positive value, and this gets converted back to be between [1, 127].
In this conversion process, it currently rounds down at all times which results in tiny weaponry able to still harm strong blocks.

A block set to 100 000 max hp can receive 1 cannon damage and it would be rounded down to 126 when the real value is something like 126.99. This results in this tiny projectile dealing 787 damage in comparison.

This is an extreme example, and here the block should simply be unharmed. Normal rounding applied here would be best where 126.5 or above becomes 127 again. and 126.4999 or below becomes 126. You would need to apply at least 393 damage in this example to harm the armor block and although that is still not close to the required 787 damage, it's the best solution to allow HP values to exceed 127.