Hi, I have recently found issues in compiling the Kernel code branch downloaded from https://github.com/UDOOboard/linux_kernel -> branch imx_3.14.28_1.0.0_ga_a62. I am following the instructions posted at the link: http://download.udoo.org/files/a62/UDOObuntu2/instructions_kernel_compiling.txt I was previously able to go through the kernel compilation steps without any issue. I have recently set-up a new Ubuntu 16.04 LTS PC, identical in configuration as the previous one where the compilation is still working fine. The only difference is that I have downloaded fresh code from the https://github.com/UDOOboard/linux_kernel on the new PC. Here the process I am following: git clone https://github.com/UDOOboard/linux_kernel cd linux_kernel/ git checkout imx_3.14.28_1.0.0_ga_a62 make ARCH=arm seco_a62_defconfig make ARCH=arm menuconfig make -j8 CROSS_COMPILE=arm-linux-gnueabihf- ARCH=arm zImage modules dtbs If I avoid to checkout the github using the imx_3.14.28_1.0.0_ga_a62 branch, the compilation succeed. If apply the git checkout to imx_3.14.28_1.0.0_ga_a62, the compilation is crashing with the following error messages: (...) cache-l2x0.c.text+0x974): multiple definition of `nop_dma_unmap_area' arch/arm/mm/dma-mapping.o:dma-mapping.c.text+0x1314): first defined here scripts/Makefile.build:387: recipe for target 'arch/arm/mm/built-in.o' failed make: *** [arch/arm/mm/built-in.o] Error 1 Makefile:843: recipe for target 'arch/arm/mm' failed make: *** [arch/arm/mm] Error 2 I am attaching a log file with the entire collection of error messages. If I try to compile the kernel without the git checkout required for the SBC A62, staying with the main Udoo branch, the compilation completes successfully. Is it possible for the Udoo code developers to check potential inconsistencies in github.com/UDOOboard/linux_kernel?