Originally Posted by alkataz
My S4 will not boot when my sd card is inserted. I have tried multiple sd cards of different classes, brands, and size. I am running MK2 stock rom with root.If I do a factory reset and wipe the sd card the phone will root. Google will install all my apps and everything will work fine. But when I move more than a couple apps to the sd card (all of the apps are games nothing system related) it will not boot the next time I power off the phone and restart it again. It will hang at the glowing samsung screen. It actually looks like it tries to boot a couple times because the phone will gently vibrate while on the screen and the back light on the soft buttons will go off and come back on a few times. I even let the phone sit for over half an hour a couple times and no luck.
I am on MK2 firmware using the Modem MK2 from this forum not an OTA update. And I am on a MJA bootloader with the counter tripped. I updated to using a stock rooted MK2 rom from this site as well. But the problem started before I updated to the new stock rom and firmware.
It might also be worth noting that I am using the latest version of Philz Touch Recovery, but after I odined the latest recovery and flashed the MK2 modem, little yellow words now appear in the upper left hand corner of the Samsnung Galaxy S4 flash screen. They are too small for me to read. I reflashed Philz and the modem, but the little yellow words didn't go away and everything worked fine until I started moving apps to the SD card.
First, the little yellow words. That happens because you have a custom recovery installed. Started appearing with MJA and the implementation of the Knox enabled boot loader. No way to get read of them except to flash back to full stock/stock recovery. Don't worry, it won't affect your phone operations.
On the sdcard problem, how is your card formatted? Unless the kernel supports exfat or ntfs, you are better off formatting the sdcards for FAT32. This is the only formatting convention that works on all versions of Android. You can also try formatting the sdcard in recovery.