We know the chips cost 360 euros per board, so that means there's already 110 euro reserved for parts and labour, design etc. Increase that by maybe 30 euro for reasonable amount, and we'd get about 500 euro for a board from burnin directly. The BitBurner XX assembly etc cost about 100 euro so I don't think I'm that far off with 140 euro for parts, labour etc.
The 360 euros for the chips is based on the retail price of the chips, but i was hoping burnin may get a better deal on the chips since he will sell assambled miners and will buy them in bigger numbers, but considering the final price of the board i was awfully wrong.