Hi Solaris. I don't have the answer to your problem but I believe you may be onto something with regard to repairing the firmware that partially works on your player. I would be very interested in having that (partially-working) firmware myself. There is another application apart from EasyFW that can edit firmware files. I have the same problem and a similar-looking MP4 player to yours. If you send me your partly-working firmware, I will try to fix it to try to resolve my own broken player. If I'm successful I will send you the fixed version so you can fix yours.
So, I would be grateful if you could kindly post a link so I can download your partly-working firmware (that shows the mirrored image on screen), or else email it to me at:
gullwng@yahoo.com
Thanks