Hello, thank you for the thorough description of the issue and your troubleshooting steps thus far. Have you tried flashing a completely different image to the same SD card to see if it succeeds? Also, although all blocks were reported in good working order, I would try another SD card/reader just to be sure. It sounds like you may have already seen this explanation for the “checksum error”: Checksums do not match - #82 by zvin including a possible cause and workaround for Windows, but if not it’s worth a look as well.