Running Pavel Demin's FPGA SDR designs under RP OS image (Ubuntu) - repost

[belotserm]

Sorry, I already posted this question under the "software"forum, but then realized this is probably more of an FPGA question, so reposting here as well: can anyone think of reasons why a bit file built off of one of the Pave Demin's SDR block designs would run fine under his Alpine image but would not work properly (no reception) under the Red Pitaya's OS Ubuntu OS image? I assume the device trees should be the same, and the fabric read/write is done via /dev/mem reads/writes which should not differ for different OS kernels.
Thanks!