Is it possible to build bootloader with open source tools?

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Hi,

I am trying to build this project with Yosys/NextPNR/ecppack etc open source tool set. I collected all the *.v files in "common"
and the two *.v files in the TinyFPGA-EX project and tried to build ..

Yosys fails because it can't find the VLO module, which looks like it is supplied by the diamond tools?
ERROR: Module \VLO referenced in module \usb_pll_inst' in cell \scuba_vlo_inst' is not part of the design.

Is what I am doing possible? I am trying to port the bootloader to the Colorlight i5 V7.0 module .... (which is an ecp5 based module)

EDIT: Can I get around this by using ecppll to produce the pll code instead of diamond scuba.exe ...
I have managed to get it to build fine for this target, but have no idea how to include the necessary meta-data JSON into the image so that tinyprog will do the right thing ... any help appreciated ..