Thats not a problem anymore .
But I still only can be in CFW for 10 seconds, then it freezes.
I was having a freezing issue too.
After getting into CFW, which took a few tries, it would soon freeze up every time.
Even if I just let it sit there, after a little bit it would freeze up.
Not only have I not had freezing in the last few times I used it, but now it seems I can boot into CFW way more easily too.
Here are the things I did, but I don't know which, if any, improved the situation:
1. Made sure that sysnand was reformatted after CFW was installed and working.
2. I turned on the WiFi switch quickly after getting into CFW. (I doubt this made a difference, however.. and be careful not to leave it on too long or after restarting.)
3. I quickly went into DevMenu and installed a CIA file before the freezing happened. (Had a freeze the first time I tried this with just "Formatting" on the screen but no progress. Second time had a successful .CIA install.)
4. I also tried quickly going into some other menus.. like settings and such. (If I understand correctly, you should NOT enter "Data Management" and leaving Settings will put you back on SysNand.)
I wish I knew what did it, if it was anything I did, but there are some things you can try.
Sorry if this turns out to be of no help.