Excessively large WIC image size after remote build

Support
1

PYNQ version: 3.1

Board: AUP-ZU3 (pynqremote image build)

After successfully building the image with make pynqremote, the generated WIC image size is excessively large.

The logical image size is around 6 GB, while the actual root filesystem usage is only about 500 MB.

This results in a situation where the logical disk size is far greater than the usable size and what the project actually requires.

For a normal PYNQ image (non-remote), the image size closely matches the rootfs size + padding.

However, for the remote image, it seems that some default minimal disk size or --resize behavior is applied, causing the image to always be ~6 GB even for very small rootfs.

  • Is there a hardcoded minimum disk size when using WIC in the PYNQ remote build process?

  • Where is this value defined or controlled?

  • How can it be adjusted to generate a smaller remote image (e.g., 1 GB or less)?

  • Is this behavior intentional?

2

Hi @boxstar

The 6GB size is a Yocto WIC default, which is why it’s in there at the moment.

I actually have a fix for this that I will be pulling into the image_v3.1.3 branch soon… I just have a bit of testing I need to do first. I’ve reduced the image size down even more by removing unnecessary packages, which leaves it at less than 200MB (and reduces the build time too). My plan was to keep the image size around 500MB (over 300MB free) to account for multiple bitstreams users might keep on the board.

Just to clarify, this is for PYNQ.remote images only. The SD card image size will remain the same for Classic PYNQ.