I have an older model I haven't hacked but started looking into a bit; I'd like to enable landscape display for ePub as the current renderer cuts off long lines

I have an older model I haven't hacked but started looking into a bit; I'd like to enable landscape display for ePub as the current renderer cuts off long lines in code samples, with no way to scroll horizontally. As I recall, with that model you can boot from your own OS image by placing it on the external SD card. You can also flash the internally stored OS, if you feel particularly confident. I haven't done it, so research for yourself, if you're interested.