You can create the IFL boot media ISO file while booted to IFL. This just requires having the IFL download zip file available. See KB article (Zip File Mode): http://www.terabyteunlimited.com/kb/article.php?id=545
Have you verified that the ifl.ini file in the IFL install folder contains the license information? Also, the BOOTITBM.INI/BOOTITBM-CUSTOM.INI files if using partwork. I assume if you boot your media that no license details on in the files?
I have created test ISO files with both the CUI and GUI versions of IFL in PCLOS 2017 64-bit and they were successful (no license prompts when booted). Can you provide any more details on any steps you're doing?
The defaults work in most cases. For example, using the IFL GUI install:
1. Open a terminal and switch to root mode.
2. Change to the folder where IFL is installed (where you ran the 'setup' script).
3. Run the 'iflbuild' script.
4. Select the "Run makeISO to create custom ISO file" option.
5. Select the "Full Version with network support" option.
6. On the next screen (IFL BOOT MEDIA SETTINGS) don't change anything.
7. Select the "Finished/Exit Menu" option.
8. Option 2: Press <Enter> to retain default console login not required.
9. Option 3: Press <Enter> to retain default root password.
From that point the script will create the ISO file. Messages will be displayed. Can you provide the output you see for your build? An example is below:
Building custom full version with network support
Copying ifl-custom.ini to the root filesystem as ifl.ini
Copying config.txt to the root filesystem
Copying wireless/firmware directory to the root filesystem
Copying iscsi directory to the root filesystem
Copying tbosdtfiles directory to the root filesystem
Copying BOOTITBM-CUSTOM.INI to the root filesystem as BOOTITBM.INI
Boot Media language version is English (default)
Restore Disc language version is English (default)
Recompressing the root filesystem...please wait
Build of iflnet-custom.iso is complete
The file iflnet-custom.iso can now be burned to CD/DVD
Note that burning the ISO file is also an option in the 'iflbuild' script. The iflnet-custom.iso file (in this example) is the file you would burn.