∙ Take full backup of sd card
∙ Open Partition tool
∙ Select create from bottom left dropdown
∙ Select the Sd card from drop down. Most likely there is only one option. /dev/block/mmcblk1
∙ Use the slider to select 1st partition size. This will be your sd card detected by android and pc/laptop
∙ Select the file systems for 1st partition and 2nd partition. Select fat32 for 1st partition and ext4 for 2nd partition
∙ Click yes and follow on screen instructions.