linux – Yocto initramfs does not have enough space in rootfs during flashing

I have been trying to build a Linux image for imx6ull with Yocto. I have successfully built an older version and flashed the board using mfgtool. With Linux Gatesgarth branch i have been having problems with mfgtool so I am trying to switch to uuu.

First part of the uuu script is below;

uuu_version 1.2.39

# This command will be run when i.MX6/7 i.MX8MM, i.MX8MQ
SDP: boot -f u-boot.imx

FB: ucmd setenv fastboot_buffer ${loadaddr}
FB: download -f zImage
FB: ucmd setenv fastboot_buffer ${fdt_addr}
FB: download -f imx6ull-14x14-evk-gpmi-weim-imx6ull14x14evk.dtb
FB: ucmd setenv fastboot_buffer ${initrd_addr}
FB: download -f fsl-image-mfgtool-initramfs-imx6ull14x14evk.cpio.gz.u-boot
FB: ucmd setenv bootargs ${bootargs} ${mtdparts}
FB: acmd ${kboot} ${loadaddr} ${initrd_addr} ${fdt_addr}

FBK: ucmd cat /proc/mtd
FBK: ucmd cat /proc/mtd | while read dev size erase name; do mtd=${dev:3}; mtd=${mtd%:}; name=${name%"}; name=${name#"}; echo export $name=$mtd >> /tmp/mtd.sh; done; 

At this point device gives “No space left on device” error.

run shell cmd: cat /proc/mtd | while read dev size erasesize name; do mtd=${dev:3}; mtd=${mtd%:}; name=${name%"}; name=${name#"}; echo export $name=$mtd >> /tmp/mtd.sh; done;
sh: line 0: echo: write error: No space left on device

I am testing with a bare image with a 512mb nand flash but it seems like rootfs partition is full.

1:243>Start Cmd:FBK: ucmd echo "`df -h`"
Filesystem      Size  Used Avail Use% Mounted on
rootfs           31M   31M     0 100% /
none             31M     0   31M   0% /dev

I have tried to increase the size of the partition with IMAGE_OVERHEAD_FACTOR = "1.5" in local.conf but the error persists.

How can i increase the size of the rootfs partition in initramfs or what could be the cause of the problem?