Ethernet and disk size on RPI3B+

I've made it work just fine now on my RPI3B+ just by copying the start.elf from the latest Stretch distribution. However, when loading the grand piano, I get an error message that the memory and/or the disk is full. So my question is this....

1) is it possible to extend the disk size, just like with Raspi-config, on a SamplerBox distro? And if so, how? I get that I have only a few MBs free but in fact I have a 32 GB card. My thought is maybe that's why I can't load the piano. Other, smaller samples, work just fine.

2) How do I enable the ethernet port? I don't even get the network LEDs on the RPI to light up when attaching a cable. It's like superdead.. and it's not a hardware problem since it works with other distros.

Hi Bjorn.
I don't recognize the memory error, but the wifi surely won't work as the drivers have changed.
Please refer to http://www.samplerbox.org/forum/435 (post Sep 18, 23:17) for tech details on how & what to upgrade, this also contains info for extending the available space.
I recommend against using the the full card size, as you can use that for an extra separated partition for storing samples internally. Alex (https://samplerbox.readthedocs.io/en/latest/) already uses that and I intend to follow that in next release of my version.