CF Mod various problems: what can it be?

[squonk]

Hi!
I finally made the CF Mod on my old but still working iAudio X5L.
Hardware that I used are as follows:
1) CF to IDE adapter
2) MicroSD to CF adapter

I plugged in the adapter 2 microSD 64Gb: formatting the card, I get a 128Gb memory cards that works faster than the original microSD (I think the adapter creates a kind of raid between the two memories).

Everything works pretty well, but, unfortunately, I have several problems that occur often enough: the player stops completely, so you have to turn it off forcibly by pressing and holding the power button.
The thing takes place randomly in one of these three circumstances:
1) at boot after you see the third line (which contains the battery voltage);
2) when I access the disk and I browse through the folders to add an album to playlist;
3) when playing a song (completely random, maybe after 15-20 minutes of playing without problems).

These issues are of course very annoying and I can not figure out what it can depend on.
It could be the adapter IDE to CF? If so, there is another with better quality to buy?
Or is the microSD to CF adapter?
Is there a way to figure out the source of the problem?

Thanks for attention!