Create Bootable UEFI ISO

Question

I am trying to create a bootable UEFI ISO, but Hyper-V does not see it as a valid UEFI filesystem. What am I doing wrong?

ISO creation:

xorriso -as mkisofs -o uefi.iso -iso-level 3 -V UEFI isoFiles

isoFiles has a single file, boot/hello.efi. When mounted or opened in an archive manager the file exists.

Hyper-V output:

Edit: Let's have a lot more context for this shall we?

This is the EFI code, it uses gnu-efi v3.0.8:

#include 
#include 

EFI_STATUS efi_main(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable){
    EFI_STATUS Status;
    EFI_INPUT_KEY Key;

    ST = SystemTable;

    Status = ST->ConOut->OutputString(ST->ConOut, L"Hello world!

");
    if(EFI_ERROR(Status)){
        return Status;
    }

    Status = ST->ConIn->Reset(ST->ConIn, FALSE);
    if(EFI_ERROR(Status)){
        return Status;
    }

    while((Status = ST->ConIn->ReadKeyStroke(ST->ConIn, &Key)) == EFI_NOT_READY){}

    return Status;
}

This is the Makefile for it:

DIR_OUT     := ..
TARGET      := uefi
OUT         := $(DIR_OUT)/out/boot

DIR_SRC     := src
DIR_BLD     := build

EFI_DIR     := gnu-efi-3.0.8
EFI_LIB     := $(EFI_DIR)/x86_64/gnuefi/ $(EFI_DIR)/x86_64/lib
EFI_INC     := $(EFI_DIR)/inc $(EFI_DIR)/inc/x86_64 $(EFI_DIR)/inc/protocol
EFI_CRT     := $(EFI_DIR)/x86_64/gnuefi/crt0-efi-x86_64.o
EFI_LDS     := $(EFI_DIR)/gnuefi/elf_x86_64_efi.lds

CFILES      := $(wildcard $(DIR_SRC)/*.c)
OFILES      := $(patsubst $(DIR_SRC)/%.c,$(DIR_BLD)/%.o,$(CFILES))

PREFIX      := 
CC          := $(PREFIX)gcc
LD          := $(PREFIX)ld
OBJCPY      := $(PREFIX)objcopy

INCLUDES    := $(addprefix -I,$(EFI_INC))
CFLAGS      := -fno-stack-protector -fpic -fshort-wchar -mno-red-zone -Wall -ffreestanding -DEFI_FUNCTION_WRAPPER -c $(INCLUDES)
LDFLAGS     := -nostdlib -znocombreloc -T $(EFI_LDS) -shared -Bsymbolic $(addprefix -L,$(EFI_LIB)) $(EFI_CRT)

all: builddir bootdir $(OUT)/$(TARGET).efi

.PRECIOUS: $(OFILES)

clean:
    rm -vrf $(OFILES) $(OUT)/$(TARGET).efi

$(OUT)/$(TARGET).efi: $(DIR_BLD)/$(TARGET).efi
    cp $< $@

%.efi: %.so
    $(OBJCPY) -j .text -j .sdata -j .data -j .dynamic -j .dynsym  -j .rel -j .rela -j .reloc --target=efi-app-x86_64 $^ $@

$(DIR_BLD)/$(TARGET).so: $(OFILES)
    $(LD) $(LDFLAGS) $< -o $@ -lefi -lgnuefi

$(DIR_BLD)/%.o: $(DIR_SRC)/%.c
    $(CC) $(CFLAGS) $< -o $@

bootdir:
    mkdir -p $(OUT)
builddir:
    mkdir -p $(DIR_BLD)

This is the Makefile that creates the ISO:

ISO_DIR     := ..
ISO_FILE    := uefi.iso
ISO_LABEL   := UEFI

DIR_BLD     := build

MKFSISO     := xorriso -as mkisofs

FATSIZE     := 8M
MKFSVFAT    := /sbin/mkfs.vfat
MOUNT       := sudo mount
UMOUNT      := sudo umount

UID         := $(shell id -u gudenau)
GID         := $(shell id -g gudenau)

all: buildDir $(ISO_DIR)/$(ISO_FILE)

.PRECIOUS: $(ISO_DIR)/$(ISO_FILE) $(DIR_BLD)/efi.img

$(ISO_DIR)/%.iso: $(DIR_BLD)/efi.img
    $(MKFSISO) -o $@ -iso-level 3 -V "$(ISO_LABEL)" $(DIR_BLD)/efi.img -e /efi.img -no-emul-boot

%.img:
    dd if=/dev/zero of=$@ bs=1024 count=1024
    $(MKFSVFAT) $@
    mkdir -p $(DIR_BLD)/image
    $(MOUNT) -o gid=$(GID),uid=$(UID) $@ $(DIR_BLD)/image
    mkdir -p $(DIR_BLD)/image/EFI/BOOT/
    cp ../bootloader/build/uefi.efi $(DIR_BLD)/image/EFI/BOOT/BOOTX64.EFI
    $(UMOUNT) $(DIR_BLD)/image
    rm -vfr $(DIR_BLD)/image

clean:
    rm -vf $(DIR_BLD)/efi.img $(ISO_DIR)/$(ISO_FILE)

buildDir:
    mkdir -p $(DIR_BLD)

I know the Makefiles are really bad at the moment, but I am just trying to get it to work at the moment. I will make them better later.

Edit: After more research I have this Makefile now:

ISO_DIR     := ..
ISO_FILE    := uefi.iso
ISO_LABEL   := UEFI

DIR_BLD     := build

MKFSISO     := xorriso -as mkisofs

FATHEADS    := 32
FATTRACKS   := 32
FATSECTOR   := 512
FATTHING    := 128
FATFORMAT   := mformat

MMD         := mmd
MCOPY       := mcopy

all: buildDir $(ISO_DIR)/$(ISO_FILE)

.PRECIOUS: $(ISO_DIR)/$(ISO_FILE) $(DIR_BLD)/efi.img

$(ISO_DIR)/%.iso: $(DIR_BLD)/efi.img
    $(MKFSISO) -o $@ -iso-level 3 -V "$(ISO_LABEL)" $(DIR_BLD)/efi.img -e /efi.img -no-emul-boot

%.img:
    $(FATFORMAT) -i $@ -F -h $(FATHEADS) -t $(FATTRACKS) -n $(FATTHING) -c 1 -C
    $(MDD) -i $@ ::/EFI
    $(MDD) -i $@ ::/EFI/BOOT
    $(MCOPY) -i $@ ../bootloader/build/uefi.efi ::/EFI/BOOT/BOOTX64.EFI

clean:
    rm -vf $(DIR_BLD)/efi.img $(ISO_DIR)/$(ISO_FILE)

buildDir:
    mkdir -p $(DIR_BLD)

But I can not figure out how to make a GPT image with it, as mkgpt does not seem to exist.

Create Bootable UEFI ISO

Answers (1)

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