I’ve had a few issues where Ubuntu did not install grub properly during install, you can either run the grub-install /dev/sda before reboot OR if you missed it, download ww.supergrubdisk.org/ to load the OS and then fix grub.
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I’ve had a few issues where Ubuntu did not install grub properly during install, you can either run the grub-install /dev/sda before reboot OR if you missed it, download ww.supergrubdisk.org/ to load the OS and then fix grub.