Thanks for the input guys. I've checked the html file multiple times, it's clean (even did HTML-Tidy).
I've tried the epub-to-epub conversion, but it doesn't fix the problem. LRF files don't show that problem at all.
For the ones that only work at Small-size, the text is too small for me to read it comfortably, and when I tried to increase the font-size, it gives me the blank screens at all zoom-levels.
I've attached a test-epub file that's giving me the same problem, could anyone try it on their reader see if it's displaying normally? Thanks in advance.