How to rewire 5V to 40-pin connector after reverse polarity issue?

mafish

Hi,
my Up boards are being powered from external HAT via 5V pins on 40 pin connector. Due to incorrectly made custom wire on one of the boards, the voltage was applied incorrectly (reversed polarity).
It seems to have killed something on the board, and now the 5V supplied is not carried from 40-pin connector to the Up board main power bus. The other functionality that I use (communication interfaces on the 40pin) seem to work fine, and Up board itself is working correctly when powered from barrel jack.

My question is, how can I safely rewire the Up board to pass power from 5V pins on 40pin connector to the main board? Simplest solution seems to be to connect 5V barrel jack pin directly to 5V on 40pin. Is it safe tho, or some weird voltage loops may happen?