Compiling Kernel with snd-usb-audio for RN102 6.1.4

Your base problem at least to me seems to be that the current GPL sources for the ReadyNAS OS 6 platform are missing the defconfig.arm kernel config file. The original .config file coming with the kernel source tree from NETGEAR as well as both readynas_defaultconfig files in the /arch subtree contain the configuration for x86_64 based systems which when used will of course result in kernel modules with the wrong "vermagic" and possibly some other differing settings being built.

I already contacted NETGEAR about this and I hope they can send me a copy of the kernel config for ARM or make it available by other means. Until there is a working kernel config for ARM I think it is next to impossible for you to build a working kernel module since that would require to find the right settings by trial and error :/

In the meantime to further debug your problem you may also wish to run "dmesg" after the failed loading of the module. The dmesg output often gives more information about why a module won't load.

-Stefan