GRUB install

Debian 10 preempt-RT CD installer, graphical install non-EUFI, installed to sdb1, SD and guess installed GRUB on Master Boot Record (MBR).  Boot menu show SD, select and boots okay.

Debian 10 preempt-RT CD installer, graphical install non-EUFI, installed to sdb1, USB and GRUB installed to sdb1.  Boot menu show USB, select and hangs at boot.

Does Debian 10 require booting an external device (USB) from the master boot record?  Can boot from GRUB installed on external device, prevent hanging and how resolve?  

Can a GRUB on an external device and a GRUB on the Master Boot Record either boot on the same computer?  Will the GRUB on the external device boot to another computer without a GRUB? 

Does the external device with a GRUB require a BIOS on same device?

An asterisk would of been expected at sdb1 boot that GRUB on that partition.

sdb1 and grub> inserting the kernel and initrd might boot.  sdb1 grub> presently no list hd1.  grub.cfg and maybe alter root=hd1 to root=hd0 or replacing grub.cfg file could boot.  I suppose just install grub to the Master Boot Record to boot sdb1.  Simply deleting Debian 10 and re-installing with Debian 10 installer CD could suffice but prior deletion could lose about few gigibytes.  Can the sda1 or sdb1 grub> get reconfigured to boot hd1 from hd0 and how is set explicitly?

I think deleting data and losing about a few gigabytes is remaining partitions and sometimes partitions not removable including at command prompt.

Some of the partitions wouldn't delete when using a Windows system and maybe because data written from Linux. A Linux system enabled to delete partitions including EFI and free space. 15.5GB free of 16GB.

I am lost, have no idea what is going on, but, the attached screenshot shows the SDA having issues with partitions not being inside of physical boundaries and whenever i saw that = it would not boot.
One easy way of avoiding that is to tell the installer to do automatic partitioning and use the entire disk.

The 512 bytes might be boot space.  fdisk -l and /sdb (SD) and 'Partitions not being inside of physical boundaries' probably could get ignored awhile because Debian 10 still boots.

I did guided install and auto partitioning with Debian 10 preempt-RT installer CD last time. I deleted the partitions, renamed the volume and slow formatted the 62 GB (64 GB) mini USB from Linux. I'll install the GRUB on sda1 and MBR (Ubuntu 18.04.5 LTS) next time.

GRUB should be installed on SDA, not on SDA1, but it does work either way, mostly.

Installed Debian 10 preempt-RT to 62 GB USB with CD installer.  Included installing GRUB to sda MBR.  Debian 10 auto booted after installation. Desktop files slow to response and opening.  Powered-off mini computer.  Powered-on mini computer and grub rescue displayed.  I had to set root partition, Linux kernel, and initrd image file and reference of fdisk -l and ls /boot.  Then remake the config file and reinstall Grub.  Ubuntu 18.04.5 LTS boots okay now.  I might of installed the GRUB to sdb and SD after all. 

SD might be choice to boot Debian 10 to an external drive.  LinuxCNC lathe seems to simulate okay.  Opening files responds fairly fast. 

smplc wrote:

Some of the partitions wouldn't delete when using a Windows system and maybe because data written from Linux. A Linux system enabled to delete partitions including EFI and free space. 15.5GB free of 16GB.

I've had similar issues with being unable to format Linux USBs under Windows. You can get around it by deleting the partitions with fdisk. Then it willl work