How to : Quick resize squashfs image in openwrt 19.07.3 x86–64

1. Download image builder from openwrt website
2. Extract to where you want
3. go inside openwrt image builder directory
4. edit file .config
5. change CONFIG_TARGET_SQUASHFS_BLOCK_SIZE=512 and CONFIG_TARGET_ROOTFS_PARTSIZE=512

both default value is 256

then make a image by command

make

I tested only 512m and 1024mb. a bigger than this is failed on build.

Hope this help
Happy openwrt.