Armbian building error

[leo.costa]

Hello,
i've just installed a standard Ubuntu 18.04 on a virtual machine, i've installed all requested package, i've cloned the Amrbian Olimex repository (i've tried both the master and the olimex branch), but after launching compile.sh i get always  errors:

I get the following error with the command "touch .ignore_changes" before compiling:
-----------
[ o.k. ] Syncing clock [ host ]
[ o.k. ] Checking for external GCC compilers
Specify at least one URL.
Usage: aria2c [OPTIONS] [URI | MAGNET | TORRENT_FILE | METALINK_FILE]...
See 'aria2c -h'.
[ warn ] Failed to download control file
Specify at least one URL.
Usage: aria2c [OPTIONS] [URI | MAGNET | TORRENT_FILE | METALINK_FILE]...
See 'aria2c -h'.
[ warn ] Failed to download control file
md5sum: /home/leo/ArmbianOlimex/build/cache/toolchains/gcc-linaro-7.4.1-2019.02-x86_64_arm-eabi.tar.xz.asc: no properly formatted MD5 checksum lines found
[ error ] ERROR in function download_and_verify [ general.sh:897 ]
[ error ] verification failed
[ o.k. ] Process terminated
----------

I get the following error without the touch command:
-----------
-----------
[ o.k. ] Syncing clock [ host ]
[ o.k. ] Checking for external GCC compilers
[ error ] ERROR in function download_and_verify [ general.sh:1115]
-----------

It seems the olimex armbian respository is not up-to-date with the official one, maybe with the correct gcc-linaro packages link.
I've tried the official armbian but it doesn't work with the A20-SOM-204 board.
Any suggestions?

Leo