The paradigm for booting systems changed in 2005 or so. The venerable BIOS increasingly gets replaced by UEFI (Unified Extensible Firmware Interface) that provides more support to basic functionalities (including advanced graphical/mouse support), which, however, comes at the price of increased complexity for linux systems. We are now back in the era where the boot loading sequence is one of the serious challenges of setting up a linux system (LILO had greatly simplified it and by the time of Grub, it was fairly automatic already).
My SD card doesn't mount and meets with a
mmc0: error -110 whilst initialising SD card
when plugging the card (to see what's going on as you plug and unplug, run a:
tail -f /var/log/syslog
). The error appears three times in a row. It's a registered bug (from the kernel, apparently) and may appear for certain types of card only.