error grub al instalar ubuntu 18.04.5 LTS

El error que me aparece es el siguiente:

La ejecución del <<grub-install /dev/mmcblko>> falló.
ESto es un error fatal.

Me da tres opciones de para ubicar el gestor de arranque
1. sda
2. sda1
3. No cargar motor de arranque

He elegido sda1 por las veces anteriores la eleccion de sda no hizo bueno.
Despues sda1 no ha dado problemas y me ha pedido que reinicie.
Y cuando reinicio me pide el USB o me va al boot menu a que elija el disco duro.
Pero se queda en un bucle y no hace nada.

We need diagnostic information about your system:

Start your computer with the installer in the mode "Try Ubuntu without installing".
Then open a terminal window and issue the commands

lscpu
sudo fdisk -l

and copy/paste all output into this question document.

(Remark: usually "sda" is the right answer for the boot loader)

¿que orden tengo que darle para cambiar el disco de arranque a SDA?

My remark about sda was related to

Me da tres opciones de para ubicar el gestor de arranque
1. sda
2. sda1
3. No cargar motor de arranque

You do not need to know about sda when executing the commands
lscpu
sudo fdisk -l

executin this commands when restar de computer go to the boot a enter in a loop

is there any kind to send a capture of the failure??

Are you able to boot the computer with the installer in the "Try Ubuntu without installing" mode?

Si. Ahora esta instalado el ubuntu 18.
Y consigo arrancarlo con "probar Ubuntu sin instalar"
¿Que tengo que hacer?

If you have already installed Ubuntu 18.04, then you do not need to try this again in the "Try" mode.

Is Ubuntu 18.04 now working normally?

No. solo está instalado y no arranca

What do you see when you try starting Ubuntu?

error code appears and keeps running
and then on a black background a small BIOS menu

i can chose into a CD, HDD0 y LAN. neither does anything

I am sorry, but the language barrier is too big, that I can help you further.
Is there a local Ubuntu user group somewhere near you?

I'm sorry too.
Tell me what I have to do to start it alone, please.
Do not give up

I suggest that you re-start from the beginning.
Start with the USB stick to install Ubuntu.
When the system asks where to install the boot loader, select sda.

yes. I have already done this every time, about 6 or 7 times

What exactly happens when you try starting your Ubuntu system?
Which error messages do you see?

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