The addition of $\mathrm{HI}$ in the presence of peroxide catalyst does not follow anti-Markovnikov's rule…
The addition of $\mathrm{HI}$ in the presence of peroxide catalyst does not follow anti-Markovnikov's rule because :
$\mathrm{HI}$ is a strong reducing agent.
$\mathrm{H-I}$ bond is too strong to be broken homolytically.
$\mathrm{I}$ atom combines with $\mathrm{H}$ atom to give back $\mathrm{HI}$.
Iodine atom is not reactive enough to add across a double bond.
Solution
$\mathrm{HI}$ does not exhibit peroxide effect. $\mathrm{HI}$ bond although dissociates easily into iodine radicals, they being bigger in size are not much reactive but recombine together to form iodine molecule.