Hi Jeff,
It seems like your build crashes because your VM is running out of memory (looking up the crash message you’re seeing is discussed here and here, where the solution was to add more swap/ram space.
Unfortunately some of the bitstreams for the Z2 have to be built as part of the pynq package (it happens in this script). You don’t have to rebuild the Pynq-Z1 and ZCU104 bitstreams however by providing the prebuilt sdist with the PYNQ_SDIST flag.
Thanks
Shawn