In the nanopcT3+ board I need to enable the I2S1 (14 pin header) in Lubuntu version.
I need to have the I2S1 peripheal as SLAVE and a MCLK of 48kHz and 192kHz (better if other clock speed are supported).
The "aplay -l" and "arecord -l" commands must show the I2S1 as a sound card with input ad output device with null device driver.

I've tried to do the job but I'm a newbbie on linux and embedded linux. Following the wiki, on a host PC I've downloaded the kernel source, modified the dtsi file to enable i2s, recompiled the kernel and U-boot and all steps seem work fine.

Now I don't know how to do a final steps to have a SD bootable image with eflasher to load and test my distro in the NanoPC T3+ emmc.

Anyone can explain step by step (from download the source code up to flash the bootable image (also with emmcflasher inside) to SDcard) how to do to enable this feature in Lubuntu.
Thanks in advance