pepe, I've done quit a bit of testing on both the sd card and firmware. My results are exactly what I expected, the sd card is trash! No need to pull your hair out trying to figure out what went wrong at least as far as I'm concerned.
I tried a different sd card and all works fine as intended!
Perhaps the SanDisk Ultra 32Gb disk should be blacklisted for the arch distro or perhaps all SanDisk Ultras! I replaced the SanDisk Ultra with a SanDisk Extreme 32Gb and have NOT had one crash at all.
I don't know if you have the power to do such a thing or not but it is a suggestion to keep others from becoming frustrated to the point of trashing the RPI. I've had nothing but problems with the SanDisk Ultra 32Gb sd card from the moment I inserted it into the RPI and ran pacman -Syu!!! I know that sometimes bad products do make it through the manufacturing process but what I nightmare trying to figure this out!
Constant crashes and sometimes not even being recognized by the RPI at least by what the on-board LEDs indicate!
Sorry if this has caused head aches for you but imagine the head ache I've had with this sd card!
Hope this head ache didn't interfere with your holiday. Once again sorry for the trouble this has caused.
And to the poster making claims without knowing all the facts you paint a picture with a pretty broad brush one day it will come back to bite you. What works on your RPI just may not work on some one else's and the reverse can also be true that what works on mine may NOT work on yours. To negate problems that others are having by claiming it works without knowing all the facts goes beyond what is allowed to be posted on this board! If you have NOTHING CONSTRUCTIVE to add that may be helpful to the people with the problem WHY POST AT ALL!