No sooner...than

Hi...

As soon as he set foot on the island, he looked for a place to hide.

(Changing into No sooner than...)

1. No sooner did he set foot on the island than he looked for a place to hide.

2. No sooner had he set foot on the island than he looked for a place to hide.

My question is which one (1 or 2) is correct? Are both correct? Pls answer my question...

Thanks in advance...