I did not major in electronics, so some of my mod may not be reasonable, but it doesn't hurt trying.
Below is my mod:
first, c7/c8 changed to MLCC, because someone mentioned that according to spec, these capacitors are served as charge pump and operated in high frequency, thus MLCC should be more appropriate than electrolytics
second, I removed IR receiver and associated R12, and break JP2, since we can control runeaudio with a smartphone, IR receiver/remote are not required
third, I changed C9 and connect several capacitors in parallel (0.1, 2.2, 10 uF), this seems to serve as filter after the regulator
For the power part, I followed TommyBoy, removed DC/DC, C1, C20, R8 (shorted, in the back), FB1 (shorted), and add capacitors (0.1, 2.2, 10, 220 uF in the back) in parallel. Well I have ordered the wrong 220 uF (100 VDC), so it's HUGE and seems overkill
For the 1 ohm resistor, I use a regular through-hole one instead of SMD component, but it should work as well
Overall, the result looks like this:
now I am very happy with it and enjoy the music