Modifying the behavior of up and down arrows with ash history on LEDE

I'd like the ash shell in LEDE to honor up and down arrow for faster history completions. I've done this in the past by simply adding the following to /root/.inputrc

"\e[A":history-search-backward
"\e[B":history-search-forward

I created that file but when I log in with ssh, I don't see that the shell is reading it. Thoughts are welcome and thanks!