Who is to bear the loss of the equipment that the questioner bought at his friend's request, and then it turned out that it did not meet the required specifications?

What is understood from the question is that you bought the equipment for yourself for your friend to work with, and you consulted him on the type to buy. He advised you based on what he knew and did not deceive you. Therefore, he is not liable even if he made a mistake, as an advisor is entrusted and does not guarantee against errors. Consequently, you bear the loss alone. There is no objection to your agreement that the profits from his work with the machines be shared equally.