The voyage is going to have the 1.8v pin somewhere else too.
This image shows something labeled 1v8 under the pink box, which looks to be avialable even before they removed the shields. On the back that one appears to be the 'MCU_1v8 pin"
https://www.ifixit.com/Teardown/Kind...Teardown/32278 step 11
https://d3nevzfk7ii3be.cloudfront.ne...AAVZXCAkQ.huge
The back of the voyage board looks better labeled, you can see UART_RX and UART_TX here
https://d3nevzfk7ii3be.cloudfront.ne...F6aXWTH1Q.huge ( but even the thinnest wires are too thick to put under the board and screw it back down. and any solder would be way to thick.