[SOLVED] root=PARTUUID= in capitals not found during boot

[MilanKnizek]

After recent update [1], RPi 2 failed to boot from external drive due to problem with root=PARTUUID=XXX option.

I eventually resolved that by changing the letters from uppercase to lowercase.

Although Google says it should be written in minuscule letters, it used to work with capital letters until now. (And I am quite sure I did not type the PARTUUID myself but I did copy & paste from some other command output or most probably directly from /dev/disk/by-partuuid/. I use only Linux tools, mostly Arch.)

[1] Not sure, which package deals with the issue, but the last update included:
$this->bbcode_second_pass_code('', 'util-linux (2.29.2-1 -> 2.29.2-2)
linux-raspberrypi (4.9.16-1 -> 4.9.19-1)
raspberrypi-bootloader (20170319-1 -> 20170331-1)
raspberrypi-bootloader-x (20170319-1 -> 20170331-1)
raspberrypi-firmware (20170319-1 -> 20170321-1)')

So, this one was nasty, since my RPi is in the cellar with quite a difficult access. Hopefully, it helps others to save some time.