I am more of a do-er and troubleshooter as I go than a teacher, so I apologize if this guide is not clear. Hopefully you can use your own intuition and skills to understand what I'm saying as I cannot articulate well and may be a little messy with this guide. That being said, please read and be sure you understand it fully before attempting it. Don't blame me if something breaks. in fact, I suggest using the recovery screen to do a full backup of all your data, boot, system and store it safe on a PC.
I know LG Optimus don't come with much memory but I wanted to tell you that you can edit the phone to boot from the external SD card, maybe this is known already, but I am the only one I know who has done this. This is better than using an app to move apps to external because it makes the phone actually read as having much more space available in system, and data. I recommend a class 10 card for speed, but class 6 may be enough I haven't tried a 6.
You need to edit your boot rom. The boot rom is lokified and needs to be unlokified, unpacked, repacked and re-lokified with your mods. You can use a Loki tool
You will need to dump the boot image from a recovery screen like TWRP. Any recovery with terminal and boot image dumping is great. Save the image somewhere safe like on your PC or the second smaller partition of the ExternalSD card. Don't save it on the large external partition because that's going to get overwritten anyways.
Example: Partition 1 will be called /dev/block/mmcblk1p1 can be large
Partition 2 /dev/block/mmcblk1p2 can be small, save tools and images here
you can make these partitions from a Linux PC and card reader or using AParted in the Google Play store.
the extra partition will be handy for future but not really needed if you use the internal phone memory to store the tools and images to do the unpacking and repacking of the boot image we saved.
http://rootzwiki.com/topic/41841-lo...tom-boot-image-on-att-and-verizon-galaxy-s-4/ to do the unlokify and relokify proceedure.
You can use Carliv Image Kitchen for Android
http://forum.xda-developers.com/android/development/tool-cika-carliv-image-kitchen-android-t3013658
The boot image cannot be unpacked and edited if it is lokified.
so you need to unlokify it.
you need a Micro SD card (Class 10) or better, whatever fits your preferences. I used a Sandisk 64Gig Ultra (10) with two partition. One is 15 gig that it reads as FAT. The rest is 43ish which is the boot ext drive.
boot to a recovery on your Optimus F3 that has a terminal, I'm using TWRP
in the terminal you will find using the command mount that /data is mounted as something like /dev/block/mmcblk0p15
this means that the data directory is mounted on the internal device 0 and partition 15.
we want to change that to mount from the external SD card, but only after we have done a dd copy of the /dev/block/mmcblk0p15 to the external SD card. Doing this will copy all of your data needed for boot and file structure over to the ExtSD card.
you can do this many different ways, from terminal in recovery, or you can dump the Data partition into a file to do this on a PC/Linux PC using a card reader. Whatever you decide.
Example: from TWRP Recovery terminal: dd if=/dev/block/mmcblk015 of=/dev/block/mmcblk1p1
this will copy the /Data partition to the external SD card partition 1. (Assuming all phones mount at the same partition, mine may be different so use caution and research of your own.)
Now that the data is copied, I like to put the ExtSD card into a linux PC and shrink, then grow the partition just to update the size difference in case the partition info is inaccurate from the copy. I don't think this is necessary but I did it anyway. You decide if you want to or not.
You can do this next part in Windows, Linux or from the TWRP Terminal. I did it on Linux for convenience of typing and editing :
use the loki tool to de-lokify the boot image you copied in TWRP.
use carliv image kitchen to unpack the delokified boot
edit the fstab.qcom in the extracted files so that Data is mounted from your external SD card that we DD the data to. So if you see /dev/block/mmcblk0p15 /Data change it to/dev/block/mmcblk1p1 /Data or whatever your individual requirements are. It could be that you partition many partitions on the ExtSD card, then the number may be different according to your desires. If you don't know the partition number, in terminal from TWRP use command blkid and look for it.
use the loki tool to re-lokify the boot image
This following part needs to be done from the recovery mode of your phone.
boot into your TWRP recovery on the phone and open terminal. in Terminal find the Loki tool (you may have saved it on the phone internal memory. Or if you made multiple partitions on the ExtSD card you can save the loki tool and files there, and mount that partition, then use the tools. use it to flash the new boot image.
when done you should be able to reboot the phone. It will boot from External SD card if done properly.
if it is broken, you have saved a backup of the data partition and boot image. Just use TWRP to re-flash the backups and try again, maybe there's something you missed.
Finally, enjoy extra storage.
I know LG Optimus don't come with much memory but I wanted to tell you that you can edit the phone to boot from the external SD card, maybe this is known already, but I am the only one I know who has done this. This is better than using an app to move apps to external because it makes the phone actually read as having much more space available in system, and data. I recommend a class 10 card for speed, but class 6 may be enough I haven't tried a 6.
You need to edit your boot rom. The boot rom is lokified and needs to be unlokified, unpacked, repacked and re-lokified with your mods. You can use a Loki tool
You will need to dump the boot image from a recovery screen like TWRP. Any recovery with terminal and boot image dumping is great. Save the image somewhere safe like on your PC or the second smaller partition of the ExternalSD card. Don't save it on the large external partition because that's going to get overwritten anyways.
Example: Partition 1 will be called /dev/block/mmcblk1p1 can be large
Partition 2 /dev/block/mmcblk1p2 can be small, save tools and images here
you can make these partitions from a Linux PC and card reader or using AParted in the Google Play store.
the extra partition will be handy for future but not really needed if you use the internal phone memory to store the tools and images to do the unpacking and repacking of the boot image we saved.
http://rootzwiki.com/topic/41841-lo...tom-boot-image-on-att-and-verizon-galaxy-s-4/ to do the unlokify and relokify proceedure.
You can use Carliv Image Kitchen for Android
http://forum.xda-developers.com/android/development/tool-cika-carliv-image-kitchen-android-t3013658
The boot image cannot be unpacked and edited if it is lokified.
so you need to unlokify it.
you need a Micro SD card (Class 10) or better, whatever fits your preferences. I used a Sandisk 64Gig Ultra (10) with two partition. One is 15 gig that it reads as FAT. The rest is 43ish which is the boot ext drive.
boot to a recovery on your Optimus F3 that has a terminal, I'm using TWRP
in the terminal you will find using the command mount that /data is mounted as something like /dev/block/mmcblk0p15
this means that the data directory is mounted on the internal device 0 and partition 15.
we want to change that to mount from the external SD card, but only after we have done a dd copy of the /dev/block/mmcblk0p15 to the external SD card. Doing this will copy all of your data needed for boot and file structure over to the ExtSD card.
you can do this many different ways, from terminal in recovery, or you can dump the Data partition into a file to do this on a PC/Linux PC using a card reader. Whatever you decide.
Example: from TWRP Recovery terminal: dd if=/dev/block/mmcblk015 of=/dev/block/mmcblk1p1
this will copy the /Data partition to the external SD card partition 1. (Assuming all phones mount at the same partition, mine may be different so use caution and research of your own.)
Now that the data is copied, I like to put the ExtSD card into a linux PC and shrink, then grow the partition just to update the size difference in case the partition info is inaccurate from the copy. I don't think this is necessary but I did it anyway. You decide if you want to or not.
You can do this next part in Windows, Linux or from the TWRP Terminal. I did it on Linux for convenience of typing and editing :
use the loki tool to de-lokify the boot image you copied in TWRP.
use carliv image kitchen to unpack the delokified boot
edit the fstab.qcom in the extracted files so that Data is mounted from your external SD card that we DD the data to. So if you see /dev/block/mmcblk0p15 /Data change it to/dev/block/mmcblk1p1 /Data or whatever your individual requirements are. It could be that you partition many partitions on the ExtSD card, then the number may be different according to your desires. If you don't know the partition number, in terminal from TWRP use command blkid and look for it.
use the loki tool to re-lokify the boot image
This following part needs to be done from the recovery mode of your phone.
boot into your TWRP recovery on the phone and open terminal. in Terminal find the Loki tool (you may have saved it on the phone internal memory. Or if you made multiple partitions on the ExtSD card you can save the loki tool and files there, and mount that partition, then use the tools. use it to flash the new boot image.
when done you should be able to reboot the phone. It will boot from External SD card if done properly.
if it is broken, you have saved a backup of the data partition and boot image. Just use TWRP to re-flash the backups and try again, maybe there's something you missed.
Finally, enjoy extra storage.