I apologize for the formatting in my last post, I don't know what happened. And many thanks for your help!
I checked my partition table using "sudo parted /dev/sda print" and it didn't show any flags for partition 1 (the "init" partition). Therefore I manually set the flags using "sudo parted /dev/sda set 1 boot on" and now it shows both flags, "boot" and "esp": Model: ATA ADATA XM11 256GB (scsi) Disk /dev/sda: 256GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags: Number Start End Size File system Name Flags 1 1049kB 128GB 128GB fat32 init boot, esp 2 128GB 256GB 128GB ext4 root However, after reboot, the ESC boot menu still doesn't show an entry for the installed system.
