> This is the 4-in-1 card reader; the one you want you are trying to boot
> from. As indicted by /dev/mmcblk0p1 it is on the PCI bus. 'lspci' should
> display the chip used; one from Ricoh?
>
> GRUB doesn't see anything on this bus (it has no drivers for the device),
> so booting from it is not possible.
Of course it all depends on what you mean by "booting from". AFAICT in
Leandro's situation, he's loading Grub from some other disk (probably
the main HDD or SSD), so he's already "not booting from the SD card" in
this sense.
Based on what I see above, his normal boot has 3 steps (ignoring the
earlier BIOS/UEFI booting itself):
1- load/start Grub
2- load/start vmlinuz+initrd
3- load/start /sbin/init from the LABEL=TAILS partition
All 3 parts can be stored at different places. My guess is that step
1 fetches its data (Grub's code as well as grub.cfg) from some HDD or
SSD. Apparently step 2 can't fetch its data from the SD card.
But step 3 can definitely fetch its data from the SD card. So all you
need is to put your vmlinuz+initrd onto a disk that Grub can see
(e.g. alongside Grub rather than in the LABEL=TAILS partition).
Stefan
