How can I go back from custom_url ipxe file to the tftp ones?

[shalak]

In boot.cfg I added:

set custom_url http://netbootxyz-nginx.my-domain.net:8080

Now, the Custom URL Menu shows up in the main, tftp-loaded menu, because there is a http://netbootxyz-nginx.my-domain.net:8080/custom.ipxe created:

#!ipxe

:start
menu Please choose an option:
item systemrescue ${space} System Rescue CD
item clonezilla ${space} Clonezilla
item ubcd ${space} Ultimate Boot CD (UBCD)
item exit Exit
choose --default systemrescue --timeout 5000 selected
goto ${selected} ||
chain ${selected}.ipxe

:exit
exit

As shown above, the main goal is to have at hand only the entries I'm most interested in (i.e. I have cached them in LAN).

However, the chain ${selected}.ipxe doesn't seem to find the tftp-loaded files and when I select it, I get the "No such file or directory" error:

How can I do chain back to the native menus? From what I saw in the menu.ipxe file, over there, the chain {menu}.ipxe works just fine...

(the goto is there for future-proofing, I may want to have some custom items that will be loaded from this file)