How do I test all USART on nucleo-f411re?

On a nucleo-f411re board there are 3 USARTs (0, 1 and 6), where to my knowledge the first one is used as stdio. When using the test program from RIOT_BASE/tests/periph_uart, where BOARD=nucleo-f411re is added to Makefile only one available device appear:


Available devices: 1 Any idea how UARTS 1 and 6 might be tested this way ?

I’m using RIOT version #936696fd.