When  I transfer my H1B from company A to B, do my spouse needs to transfer H4 along with my H1B too? The H4 is still valid for one more year.
thanks.

Yes. H4 is based on your H1. As H1 change is filed from A to B, H4 also needs to be changed.

Thanks Kg21.

But doesn't it sound odd, the H4 can't work and is completely dependent on H1B. So the common sense would have been that H1B will file for a transfer, while H4 will have to renew it (after nearing the expiration date) and only in that case prove the eligibility of H1B holder.

these laws are really funny sometimes.

Aru kasai ko pani thup experience haru chan ki yo mamila ma?