Can't disable automatic rootflags detection from fstab or set some way to ignore specific flags, resulting in broken boot entries

[GBember01]

Hi! This script is detecting some mount options from fstab that the kernel simply doesn't know and panics (like defaults, compress and noatime) resulting in unbootable snapshots.

I don't know if I'm doing something wrong, but I couldn't find any way to solve this in the config or man page.

My fstab (and subsequently the snapshots' fstabs) has the following options for the BTRFS root volume: defaults, noatime, compress=zstd:1, discard=async, subvol=/@ (which is ignored).

I'm running grub 2.12-r7 and grub-btrfs 4.13 on Gentoo

[GBember01]

I swithced to the git package (or -9999 on gentoo) to test if it changed anything, still has the same issues.
Here are the configs:

/etc/default/grub

GRUB_DISTRIBUTOR="Gentoo"
GRUB_TIMEOUT=2
GRUB_CMDLINE_LINUX_DEFAULT="amd-pstate=active"
GRUB_DISABLE_LINUX_PARTUUID=false
GRUB_DISABLE_SUBMENU=n
GRUB_DISABLE_OS_PROBER=false

/etc/default/grub-btrfs/config

#!/usr/bin/env bash
GRUB_BTRFS_VERSION=4.13-yabsnap_info_support-2024-03-06T13:43:57+00:00
GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("@")
GRUB_BTRFS_IGNORE_PREFIX_PATH=("var/lib/docker" "@var/lib/docker" "@/var/lib/docker" "var/lib/containers" "@var/lib/containers" "@/var/lib/containers")

/boot/grub/grub.cfg

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
  load_env
fi
if [ "${next_entry}" ] ; then
   set default="${next_entry}"
   set next_entry=
   save_env next_entry
   set boot_once=true
else
   set default="0"
fi

if [ x"${feature_menuentry_id}" = xy ]; then
  menuentry_id_option="--id"
else
  menuentry_id_option=""
fi

export menuentry_id_option

if [ "${prev_saved_entry}" ]; then
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
}

function load_video {
  if [ x$feature_all_video_module = xy ]; then
    insmod all_video
  else
    insmod efi_gop
    insmod efi_uga
    insmod ieee1275_fb
    insmod vbe
    insmod vga
    insmod video_bochs
    insmod video_cirrus
  fi
}

if loadfont unicode ; then
  set gfxmode=auto
  load_video
  insmod gfxterm
  set locale_dir=$prefix/locale
  set lang=en_US
  insmod gettext
fi
terminal_output gfxterm
if [ x$feature_timeout_style = xy ] ; then
  set timeout_style=menu
  set timeout=2
# Fallback normal timeout code in case the timeout_style feature is
# unavailable.
else
  set timeout=2
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/10_linux ###
menuentry 'Gentoo GNU/Linux' --class gentoo --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-8f99d32d-e667-4f1f-bce5-42680912618c' {
	load_video
	if [ "x$grub_platform" = xefi ]; then
		set gfxpayload=keep
	fi
	insmod gzio
	insmod part_gpt
	insmod btrfs
	search --no-floppy --fs-uuid --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
	echo	'Loading Linux 6.12.58-gentoo ...'
	linux	/@/boot/vmlinuz-6.12.58-gentoo root=PARTUUID=3ce16c4e-0215-4689-9b2e-ad5f964e2745 ro rootflags=subvol=@  amd-pstate=active
}
submenu 'Advanced options for Gentoo GNU/Linux' $menuentry_id_option 'gnulinux-advanced-8f99d32d-e667-4f1f-bce5-42680912618c' {
	menuentry 'Gentoo GNU/Linux, with Linux 6.12.58-gentoo' --class gentoo --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-6.12.58-gentoo-advanced-8f99d32d-e667-4f1f-bce5-42680912618c' {
		load_video
		if [ "x$grub_platform" = xefi ]; then
			set gfxpayload=keep
		fi
		insmod gzio
		insmod part_gpt
		insmod btrfs
		search --no-floppy --fs-uuid --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
		echo	'Loading Linux 6.12.58-gentoo ...'
		linux	/@/boot/vmlinuz-6.12.58-gentoo root=PARTUUID=3ce16c4e-0215-4689-9b2e-ad5f964e2745 ro rootflags=subvol=@  amd-pstate=active
	}
	menuentry 'Gentoo GNU/Linux, with Linux 6.12.58-gentoo (recovery mode)' --class gentoo --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-6.12.58-gentoo-recovery-8f99d32d-e667-4f1f-bce5-42680912618c' {
		load_video
		if [ "x$grub_platform" = xefi ]; then
			set gfxpayload=keep
		fi
		insmod gzio
		insmod part_gpt
		insmod btrfs
		search --no-floppy --fs-uuid --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
		echo	'Loading Linux 6.12.58-gentoo ...'
		linux	/@/boot/vmlinuz-6.12.58-gentoo root=PARTUUID=3ce16c4e-0215-4689-9b2e-ad5f964e2745 ro single rootflags=subvol=@ 
	}
	menuentry 'Gentoo GNU/Linux, with Linux 6.12.58-gentoo.old' --class gentoo --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-6.12.58-gentoo.old-advanced-8f99d32d-e667-4f1f-bce5-42680912618c' {
		load_video
		if [ "x$grub_platform" = xefi ]; then
			set gfxpayload=keep
		fi
		insmod gzio
		insmod part_gpt
		insmod btrfs
		search --no-floppy --fs-uuid --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
		echo	'Loading Linux 6.12.58-gentoo.old ...'
		linux	/@/boot/vmlinuz-6.12.58-gentoo.old root=PARTUUID=3ce16c4e-0215-4689-9b2e-ad5f964e2745 ro rootflags=subvol=@  amd-pstate=active
	}
	menuentry 'Gentoo GNU/Linux, with Linux 6.12.58-gentoo.old (recovery mode)' --class gentoo --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-6.12.58-gentoo.old-recovery-8f99d32d-e667-4f1f-bce5-42680912618c' {
		load_video
		if [ "x$grub_platform" = xefi ]; then
			set gfxpayload=keep
		fi
		insmod gzio
		insmod part_gpt
		insmod btrfs
		search --no-floppy --fs-uuid --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
		echo	'Loading Linux 6.12.58-gentoo.old ...'
		linux	/@/boot/vmlinuz-6.12.58-gentoo.old root=PARTUUID=3ce16c4e-0215-4689-9b2e-ad5f964e2745 ro single rootflags=subvol=@ 
	}
}

### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/25_bli ###
if [ "$grub_platform" = "efi" ]; then
  insmod bli
fi
### END /etc/grub.d/25_bli ###

### BEGIN /etc/grub.d/30_os-prober ###
menuentry 'Windows Boot Manager (on /dev/nvme0n1p1)' --class windows --class os $menuentry_id_option 'osprober-efi-8B2A-5EC8' {
	insmod part_gpt
	insmod fat
	search --no-floppy --fs-uuid --set=root 8B2A-5EC8
	chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/30_uefi-firmware ###
if [ "$grub_platform" = "efi" ]; then
	menuentry 'UEFI Firmware Settings' $menuentry_id_option 'uefi-firmware' {
		fwsetup
	}
fi
### END /etc/grub.d/30_uefi-firmware ###

### BEGIN /etc/grub.d/35_fwupd ###
### END /etc/grub.d/35_fwupd ###

### BEGIN /etc/grub.d/39_memtest86+ ###
if [ "x$grub_platform" = xefi ]; then
menuentry 'Memtest86+ 64bit UEFI' {
		insmod part_gpt
		insmod btrfs
		search --no-floppy --fs-uuid --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        chainloader "/@/boot/memtest86plus/memtest.efi64"
}
fi
### END /etc/grub.d/39_memtest86+ ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f  ${config_directory}/custom.cfg ]; then
  source ${config_directory}/custom.cfg
elif [ -z "${config_directory}" -a -f  $prefix/custom.cfg ]; then
  source $prefix/custom.cfg
fi
### END /etc/grub.d/41_custom ###

### BEGIN /etc/grub.d/41_snapshots-btrfs ###
if [ ! -e "${prefix}/grub-btrfs.cfg" ]; then
echo ""
else
submenu 'Gentoo snapshots' {
    configfile "${prefix}/grub-btrfs.cfg"
}
fi
### END /etc/grub.d/41_snapshots-btrfs ###

/boot/grub/grub-btrfs.cfg

menuentry '|         Date        |          Snapshot          |  Type  |    Description    |' { echo }
submenu '| 2025-12-23 00:00:00 | @snapshots-root/9/snapshot | single | timeline          |' {
    submenu '| 2025-12-23 00:00:00 | @snapshots-root/9/snapshot | single | timeline |' { echo }

    menuentry '  vmlinuz-6.12.58-gentoo' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-23 00:00:00 @snapshots-root/9/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo ...'
        linux "/@snapshots-root/9/snapshot/boot/vmlinuz-6.12.58-gentoo" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/9/snapshot"
    }

    menuentry '  vmlinuz-6.12.58-gentoo.old' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-23 00:00:00 @snapshots-root/9/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo.old ...'
        linux "/@snapshots-root/9/snapshot/boot/vmlinuz-6.12.58-gentoo.old" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/9/snapshot"
    }
}
submenu '| 2025-12-22 23:00:00 | @snapshots-root/8/snapshot | single | timeline          |' {
    submenu '| 2025-12-22 23:00:00 | @snapshots-root/8/snapshot | single | timeline |' { echo }

    menuentry '  vmlinuz-6.12.58-gentoo' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 23:00:00 @snapshots-root/8/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo ...'
        linux "/@snapshots-root/8/snapshot/boot/vmlinuz-6.12.58-gentoo" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/8/snapshot"
    }

    menuentry '  vmlinuz-6.12.58-gentoo.old' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 23:00:00 @snapshots-root/8/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo.old ...'
        linux "/@snapshots-root/8/snapshot/boot/vmlinuz-6.12.58-gentoo.old" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/8/snapshot"
    }
}
submenu '| 2025-12-22 22:00:00 | @snapshots-root/7/snapshot | single | timeline          |' {
    submenu '| 2025-12-22 22:00:00 | @snapshots-root/7/snapshot | single | timeline |' { echo }

    menuentry '  vmlinuz-6.12.58-gentoo' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 22:00:00 @snapshots-root/7/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo ...'
        linux "/@snapshots-root/7/snapshot/boot/vmlinuz-6.12.58-gentoo" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/7/snapshot"
    }

    menuentry '  vmlinuz-6.12.58-gentoo.old' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 22:00:00 @snapshots-root/7/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo.old ...'
        linux "/@snapshots-root/7/snapshot/boot/vmlinuz-6.12.58-gentoo.old" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/7/snapshot"
    }
}
submenu '| 2025-12-22 21:00:00 | @snapshots-root/6/snapshot | single | timeline          |' {
    submenu '| 2025-12-22 21:00:00 | @snapshots-root/6/snapshot | single | timeline |' { echo }

    menuentry '  vmlinuz-6.12.58-gentoo' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 21:00:00 @snapshots-root/6/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo ...'
        linux "/@snapshots-root/6/snapshot/boot/vmlinuz-6.12.58-gentoo" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/6/snapshot"
    }

    menuentry '  vmlinuz-6.12.58-gentoo.old' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 21:00:00 @snapshots-root/6/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo.old ...'
        linux "/@snapshots-root/6/snapshot/boot/vmlinuz-6.12.58-gentoo.old" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/6/snapshot"
    }
}
submenu '| 2025-12-22 20:00:00 | @snapshots-root/5/snapshot | single | timeline          |' {
    submenu '| 2025-12-22 20:00:00 | @snapshots-root/5/snapshot | single | timeline |' { echo }

    menuentry '  vmlinuz-6.12.58-gentoo' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 20:00:00 @snapshots-root/5/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo ...'
        linux "/@snapshots-root/5/snapshot/boot/vmlinuz-6.12.58-gentoo" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/5/snapshot"
    }

    menuentry '  vmlinuz-6.12.58-gentoo.old' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 20:00:00 @snapshots-root/5/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo.old ...'
        linux "/@snapshots-root/5/snapshot/boot/vmlinuz-6.12.58-gentoo.old" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/5/snapshot"
    }
}
submenu '| 2025-12-22 19:10:00 | @snapshots-root/4/snapshot | single | timeline          |' {
    submenu '| 2025-12-22 19:10:00 | @snapshots-root/4/snapshot | single | timeline |' { echo }

    menuentry '  vmlinuz-6.12.58-gentoo' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 19:10:00 @snapshots-root/4/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo ...'
        linux "/@snapshots-root/4/snapshot/boot/vmlinuz-6.12.58-gentoo" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/4/snapshot"
    }
}
submenu '| 2025-12-22 18:00:00 | @snapshots-root/3/snapshot | single | timeline          |' {
    submenu '| 2025-12-22 18:00:00 | @snapshots-root/3/snapshot | single | timeline |' { echo }

    menuentry '  vmlinuz-6.12.58-gentoo' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 18:00:00 @snapshots-root/3/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo ...'
        linux "/@snapshots-root/3/snapshot/boot/vmlinuz-6.12.58-gentoo" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/3/snapshot"
    }

    menuentry '  vmlinuz-6.12.58-gentoo.old' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 18:00:00 @snapshots-root/3/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo.old ...'
        linux "/@snapshots-root/3/snapshot/boot/vmlinuz-6.12.58-gentoo.old" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/3/snapshot"
    }

    menuentry '  vmlinuz-6.12.58-gentoo.old.png' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 18:00:00 @snapshots-root/3/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo.old.png ...'
        linux "/@snapshots-root/3/snapshot/boot/vmlinuz-6.12.58-gentoo.old.png" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/3/snapshot"
    }

    menuentry '  vmlinuz-6.12.58-gentoo.png' --class snapshots --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-snapshots-8f99d32d-e667-4f1f-bce5-42680912618c' {
        if [ x$feature_all_video_module = xy ]; then
        insmod all_video
        fi
        set gfxpayload=keep
        insmod btrfs
        if [ x$feature_platform_search_hint = xy ]; then
            search --no-floppy --fs-uuid  --set=root  8f99d32d-e667-4f1f-bce5-42680912618c
        else
            search --no-floppy --fs-uuid  --set=root 8f99d32d-e667-4f1f-bce5-42680912618c
        fi
        echo 'Loading Snapshot: 2025-12-22 18:00:00 @snapshots-root/3/snapshot'
        echo 'Loading Kernel: vmlinuz-6.12.58-gentoo.png ...'
        linux "/@snapshots-root/3/snapshot/boot/vmlinuz-6.12.58-gentoo.png" root=UUID=8f99d32d-e667-4f1f-bce5-42680912618c  amd-pstate=active  rootflags=defaults,noatime,compress=zstd:1,discard=async,subvol="@snapshots-root/3/snapshot"
    }
}

/etc/fstab

UUID="8B2A-5EC8"				/efi			vfat	defaults,noatime,umask=0077,tz=UTC		0 2
UUID="fb13c494-6ebd-462e-89c7-06b5bb5264fa"	none			swap	sw						0 0
UUID="8f99d32d-e667-4f1f-bce5-42680912618c"	/			btrfs	defaults,noatime,compress=zstd:1,discard=async,subvol=/@		0 0
UUID="8f99d32d-e667-4f1f-bce5-42680912618c"	/home			btrfs   defaults,noatime,compress=zstd:1,discard=async,subvol=/@home		0 0
UUID="8f99d32d-e667-4f1f-bce5-42680912618c"	/var/log		btrfs   defaults,noatime,compress=zstd:1,discard=async,subvol=/@log		0 0
UUID="8f99d32d-e667-4f1f-bce5-42680912618c"	/var/cache		btrfs   defaults,noatime,compress=zstd:1,discard=async,subvol=/@cache		0 0
UUID="8f99d32d-e667-4f1f-bce5-42680912618c"	/.snapshots		btrfs   defaults,noatime,compress=zstd:1,discard=async,subvol=/@snapshots-root	0 0
UUID="8f99d32d-e667-4f1f-bce5-42680912618c"	/home/.snapshots	btrfs   defaults,noatime,compress=zstd:1,discard=async,subvol=/@snapshots-home	0 0
UUID="01ed2331-80da-4480-b6ab-f14826f9bba1"	/hdd			ext4	defaults,noatime				0 2

[GBember01]

I'll test it out latter, but I have a suspicion this happens because the dev assumes the system is running with a initramfs. My kernel is just a binary with everything I need built in, no modules or initramfs

The kernel itself can't handle the mount options, but the tools from the ramfs can perhaps?

I'll also try to come up with a patch to disable gathering the mount options from FSTAB