I just followed the instructions I posted on the previous page and it was straight forward enough to update to firmware V3 despite being mostly in Chinese haha.
There is two big downfall's to this dap:
1) It has hardware bass roll off.
2) Bucket loads of power, 700mW@32Ω, Coupled with a cheap analog volume pot means many iems and even headphones are going to be subject to imbalance at low and even medium volume.
Basically these are the only fault's as far as sound goes imo, they are quite major faults, I couldn't use this as my only dap, but nonetheless it sounds great, it's audio processing quality easily surpasses daps like DX90 imo. It is just let down by the strange decision to roll of bass and use a cheap volume pot. Both of these issues would be possible to fix with DIY modification.
If you use the digital out of the dap it negates the issues above, and you are left with one hell of a digital source, it best's daps that cost 6x as much, and yes, digital out's do sound different, completely different, if you can't hear this then your DAC, amp, or Hp's are not up to scratch, I use a NAD M51 DAC, and digital sources sound completely different through it, just as different dacs and amps do.
.