Hello, you don't have to modify the url, I've replicated the same process without modifications, it seems like an error with your project, please try to delete your file and try again following the steps below:
4.3.2 How to download Flexbuild
Go to Downloads tab at www.nxp.com/lsdk. Download Layerscape Software Development Kit - . Enter log in details, accept the agreement to download the flexbuild source tarball in the name format flexbuild_.tgz (in this case LSDK21.08)
Oswalag_3-1707931622373.png
$ tar xf flexbuild_.tgz
$ cd flexbuild_<version>
$ source setup.env
$ flex-builder -h
please see my results below:
Oswalag_0-1707930693869.png
Oswalag_1-1707930752173.png
The images are successfully generated when running flex-builder -i mkfw -m ls1028ardb -b sd:
Oswalag_2-1707931501531.png