I have been searching all over the place for any unofficial versions of Wood R4. I came across a website containing a Wood R4 kernel labeled WAIO Wood R4. Knowing that kernel it was in .nds format I had to try it just to see if it even worked on the R4i SDHC 3DS RTS. Sure enough it booted up just fine, however you are unable to play any games while using this kernel on this flashcart. This was meant for R4 clones but I feel like this could be used for official R4 flashcarts as well if it gets tweaked.
Place I got the unofficial kernel:
http://www.mediafire.com/download/mfwrady3mm9fxaq/_WAIO+1.62+For+R4+Clones.rar
Video:
Place I got the unofficial kernel:
http://www.mediafire.com/download/mfwrady3mm9fxaq/_WAIO+1.62+For+R4+Clones.rar
Video: