Please note that the data contained in the pinmuxing files is only valid in regard of pinmuxing! All other register settings are arbitrary and only contained because it's not possible to leave them away! For opening "phyCORE-iMX6UL_1468_2_v4.0.mex" you need NXP's i.MX Pins Tool v4.0 from: https://www.nxp.com/pages/pins-tool-for-i.mx-application-processors:PINS-TOOL-IMX If you use the older NXP's i.MX Pins Tool v3.x, you need to open "phyCORE-iMX6UL_1468_2_v3.0.mex". If you use the more older NXP's i.MX Pins Tool v2.x, you need to open "phyCORE-iMX6UL_1468_2_Mainz.mex".