In order to stay safe from merrowed borders tearing edges of patch. You need to sew the BJJ patch with precision and caution. If you fail to do this, your patch will be ruined as it will be under constant abuse. If the patch is not sewn properly with the GI, it will be ruined as being pulled in different directions. In this condition, it will be only a matter of few rolls before the patch falls off. To help you avoid such circumstances, you need to try iron patches. Yes before sewing your patch, iron and meld it in the right position.
Never sew the Brazilian Jiu Jitsu Gi patches through outside border. This will help you stopping most of the problems. For better results, just sew your patch in inside merrowed border. This will secure your patch without even ruining it.