[help] newbie cant boot off http

[biatche]

following " robinsmidsrod / _INSTALL.md " example...

how do i boot an image via http?

Code:

:memtest
echo Booting Memtest86 4.2.0
chain ${boot-url}/memtest/memtestp.bin
goto start

gives

Code:

http:...................memtestp.bin...ok
Could not boot: Requested memory not available
Could not boot image: Requested memory not available
No more network devices
ctrl-b...

press any key to reboot

what have i done wrong?