In i.MX8M Mini reference manual <http://nxp.com/doc/imx8mmrm>, 18.104.22.168 it said "Before going into USB serial mode, Boot ROM detect SD/MMC card on USDHC2 port. If a card is inserted, ROM will try to boot from it. This is the so-called Manufacture SD/MMC boot".
But in table 6-22, the CD_B of USDHC2 is empty.
So which pin is for detecting USDHC2 card insert in i.MX8M Mini manufacture mode?