Once you run petalinux-config and create the device tree files, you will need to modify them. For this specific purpose of removing uart0 from the devicetree, add the following at the end of subsystems/linux/configs/device-tree/system-top.dts &ps7_uart_0 { status = "disabled"; }; Now do a petalinux-build and you are good to go. BTW: I noticed a problem with the early version of xapp1078 and I will update the wiki page but while you are editing the device tree file, also add the following for the ethernet phy device: &ps7_ethernet_0 { phy-handle = <&phy0>; mdio { #address-cells = <1>; #size-cells = <0>; phy0: phy@7 { compatible = "marvell,88e1116r"; device_type = "ethernet-phy"; reg = <7>; } ; } ; }; And one last note: if you decided not to use uart0 for cpu1 and wanted to use it for Linux, you need to change the device tree file as follows: replace: / { }; with: / { aliases { serial0 = &ps7_uart_1; serial1 = &ps7_uart_0; ethernet0 = &ps7_ethernet_0; }; };