Unhappy Problematic Grouper after root

Hello dear community,

Because he needed OTG storage access I rooted my nephew's Grouper using Universal Android Toolbox two days ago. Thing is I was in a hurry and choose the 4.4 version inside the toolbox (not 4.4.2 as it is installed on the device). 4.4 was the latest Android version available for Nexus 7. Since then, he told me that the tablet is slower and reboots every now and then. I've checked it myself and I can confirm it. Chrome and the launcher crashed on me at least once and the tablet rebooted at least twice. The only two apps with root access are BusyBox and chainfire's StickMount.

Is the rooting method for 4.4.2 so different than the one for 4.4 that it could cause problems?

I can say I have some experience with modding (applying others' work) but I can't figure out where these problems are coming from.

Thanks!

PS: I can only come with logs in a week or so.
Nokia 5110 > Alcatel OT303 > Nokia 3310 > Nokia 1100 > Nokia 1112 > Nokia 5000 > Nokia 6555 > Nokia 3120C > Nokia E51 > Nokia E52 > Motorola Defy > Galaxy Nexus

<-- Hit THANKS if this post helped you!