I tried again, with the removal of the SCRIPT line. Now I'm having the same result as with the CMDLINE='root= ..." version we were trying before. Getting loads of mmblck1: error -110 lines in succession reading/receiving for minutes (already 8 minutes ...) in a row. This is now the 2nd card I'm putting in giving this issue. But this one hasn't even fallen through yet to Nemo, as the first one finally did.

I did see something on the Nemo install wiki :
But I have a hard time believing 2 cards, different vendors, both Samsung 8 GB, one class 10, one class 6, are both defect.

So there must be something else ...

UPDATE: now I'm having the thousands of scrolling errors on mmcblk0. Same error -110 sending/receiving ...