This ramdisk is about 4MB and a lager ramdisk might be needed. This page illustrates how to make a new larger ramdisk and copy the old files to the new ramdisk. These instructions assume you are user root or have sudo privielges.

Expanding Disk File System 4MB to 8MB

A ramdisk image can be downloaded from Zynq Releases.

Make an 8MB ramdisk

dd if=/dev/zero of=initrd.img bs=1M count=8

Format new ramdisk(initrd.img)

mke2fs -F -v -m0 initrd.img

Mount initrd.img to /mnt/new-disk

mkdir /mnt/new-disk
mount -o loop initrd.img /mnt/new-disk

Gunzip & mount ramdisk to old-ramdisk (/mnt/old-disk) file

mkdir /mnt/old-disk
gunzip ramdisk.image.gz
mount -o loop ramdisk.image /mnt/old-disk

Copy ex-files to new ramdisk

cp -rf /mnt/old-disk/* /mnt/new-disk

Umount the ramdisks

umount /mnt/old-disk
umount /mnt/new-disk

Gzip new ramdisk

gzip -9 initrd.img
mv initrd.img ramdisk.image.gz
Note that the Linux kernel configuration parameter BLK_DEV_RAM_SIZE needs to be changed accordingly to reflect the new ramdisk size before building a new kernel image.
Referenced from http://tamarases.wikidot.com/expanding-disk-file-system