Is "imbedded" a valid spelling of the word "embedded"?

I have seen this used on our marketing materials:

The technology imbedded in this solution will help improve productivity.

I was going to flag it as a spelling error, however Googling provided some references to it being a proper usage.

My instinct is that it is wrong however, can anyone shed any light?

Regarding Oxford Dictionaries, yes it is:

embed

Pronunciation: /emˈbed/

(also imbed /im-/)

This is general reference, provided you have access to a good dictionary. The problem is that the free online ones often aren’t very good.

These days, imbed is commonly perceived to be a misspelling of embed perpetrated by victims of the pin–pen merger.

However, the OED2 (1989) lists imbed as an alternate spelling of embed, while pointing out that embed is now the more common form.