zyxel999
At the moment there is no support for font replacements in PRS+ (besides reflashing using igorsk's flasher, but I guess Chinese fonts are too big to do it this way, there is only about 2mb of free space in fsk flash). This way should work, however:
https://www.mobileread.com/forums/showthread.php?t=20644
Regarding re-inserting SD card: the problem, in this case, could be in either in PRS+ or in your hack, or both. Try not to do it very fast, i.e. say wait 5 sec after ejecting, before you reinsert it. I hope that helps.
PS
Next release of PRS+ will have an option to run custom shell scripts on ebook startup. This would greatly simplify integration of font replacement/ unicode/win1251 hacks.