No boot on emmc

Bought rockpi 4+ and an emmc 32g card at same time.
Installed ubuntu on sd card
booted to sd card used dd as per wiki to install onto emmc
Take out SD card wont boot
Tried other images and still no luck.

I did note that the wiki shows a .img file to dd but my file is .img.xz does this matter?
Any other suggestions to boot onto emmc please been trying this for a few hours and is becoming frustrating.
Cheers, Blair

.xz is compressed image, when you load .xz with GUI tool such as Ecther, it will automatically uncompress and write to sd ard. When you are writing to emmc with command line, you should uncompress and write it, you can use pipe, example below:

xzcat rockpi-4cplus-ubuntu-focal-server-arm64-20220520-1242-gpt.img.xz | dd of=/dev/mmcblk1 bs=1M