The I4 straps are made of two parts : one solid plastic part that is screwed in the watch and one soft part that makes the band.
Both parts got separated and here was the result :
You can see tha antenna 3M cover, the solid part is still attached to the watch.
After opening the watch (be careful that the HR sensor connector needs to be unplugged) you can extract the solid part :
And here you go with the two parts :
