Update docs/emmc-multiboot.md

2026-06-02 21:41:08 +00:00 · 2026-06-02 21:41:08 +00:00 · d4dd137a9a
commit d4dd137a9a
parent 82f844ff2d
1 changed files with 64 additions and 42 deletions
--- a/docs/emmc-multiboot.md
+++ b/docs/emmc-multiboot.md
@ -20,22 +20,25 @@ If microSD **is** inserted and has a valid bootloader, it takes priority over eM

 ## Partition Layout

+Proposed new partition schema:
 ```
 mmcblk1 (256GB eMMC)
 ├── mmcblk1boot0   (hardware boot partition — u-boot SPL + proper)
 ├── mmcblk1boot1   (unused mirror)
 └── mmcblk1
    ├── mmcblk1p1   FAT32   1GB     /boot   (extlinux.conf, kernels, DTBs — shared)
-    ├── mmcblk1p2   ext4    85GB    root1   (Orange Pi OS Arch)
-    ├── mmcblk1p3   ext4    85GB    root2   (Armbian)
-    ├── mmcblk1p4   ext4    ~84GB   root3   (NixOS)
+    ├── mmcblk1p2   ext4    85GB    root_opios   (Orange Pi OS Arch)
+    ├── mmcblk1p3   ext4    85GB    root_armbian   (Armbian)
+    └── mmcblk1p4   ext4    ~84GB   root_nixos   (NixOS)
 ```

 ### Why a dedicated FAT32 boot partition?

 u-boot reads `extlinux.conf` from a FAT, ext4, or btrfs partition. FAT32 is the most universally supported across distro kernel packages. A shared `/boot` means all three OSes drop their kernels and DTBs into one place, and a single `extlinux.conf` controls the menu. 1GB gives headroom for multiple kernel versions across all three OSes.

-## Step 1: Clone SD → eMMC (Orange Pi OS, leaves root2/root3 ready)
+## Step 1: Clone SD → eMMC
+
+Move Orange Pi OS from the microSD card to eMMC and leave two more root paritions ready for other operating systems later.

 ### 1.1 — Identify devices

@ -46,21 +49,40 @@ lsblk
 mount | grep mmcblk
 ```

-Expected: `mmcblk0` = SD card (boot device), `mmcblk1` = eMMC (target).
+Expected: 
+- `mmcblk0` = SD card (current boot device)
+- `mmcblk1` = eMMC (target boot device)
+Actual:
+- `mmcblk0` = eMMC (target boot device)
+- `mmcblk1` = SD card (current boot device)
+
+Ground truth state with only OPi OS on SD card:
+```bash
+[jez@Rocky ~]$ lsblk
+NAME         MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
+mtdblock0     31:0    0    16M  0 disk 
+mmcblk0      179:0    0   233G  0 disk 
+mmcblk0boot0 179:32   0     4M  1 disk 
+mmcblk0boot1 179:64   0     4M  1 disk 
+mmcblk1      179:96   0 238.4G  0 disk 
+├─mmcblk1p1  179:97   0 213.6M  0 part /boot
+└─mmcblk1p2  179:98   0 238.2G  0 part /
+zram0        254:0    0     0B  0 disk 
+```

 ### 1.2 — Wipe eMMC partition table

 **Destroys everything on eMMC.** Skip if eMMC is already empty.

 ```bash
-sudo sgdisk --zap-all /dev/mmcblk1
-sudo blkdiscard /dev/mmcblk1   # optional
+sudo sgdisk --zap-all /dev/mmcblk0
+sudo blkdiscard /dev/mmcblk0   # optional
 ```

 ### 1.3 — Partition eMMC

 ```bash
-sudo gdisk /dev/mmcblk1
+sudo gdisk /dev/mmcblk0
 ```

 In `gdisk` interactive mode:
@ -68,30 +90,30 @@ In `gdisk` interactive mode:
 ```
 o   (new GPT)
 n   1   default  +1G    ef00   name=boot
-n   2   default  +85G   8300   name=root1
-n   3   default  +85G   8300   name=root2
-n   4   default  default 8300   name=root3
+n   2   default  +85G   8300   name=root_opios
+n   3   default  +85G   8300   name=root_armbian
+n   4   default  default 8300   name=root_nixos
 w   (write, confirm 'y')
 ```

 ### 1.4 — Create filesystems

 ```bash
-sudo mkfs.vfat -F 32 -n BOOT /dev/mmcblk1p1
-sudo mkfs.ext4 -L root1 /dev/mmcblk1p2
-sudo mkfs.ext4 -L root2 /dev/mmcblk1p3
-sudo mkfs.ext4 -L root3 /dev/mmcblk1p4
+sudo mkfs.vfat -F 32 -n BOOT /dev/mmcblk0p1
+sudo mkfs.ext4 -L root_opios /dev/mmcblk0p2
+sudo mkfs.ext4 -L root_armbian /dev/mmcblk0p3
+sudo mkfs.ext4 -L root_nixos /dev/mmcblk0p4
 ```

 ### 1.5 — Mount and rsync the live rootfs

 ```bash
-sudo mkdir -p /mnt/root1
-sudo mount /dev/mmcblk1p2 /mnt/root1
-sudo mkdir -p /mnt/root1/boot
-sudo mount /dev/mmcblk1p1 /mnt/root1/boot
+sudo mkdir -p /mnt/root_opios
+sudo mount /dev/mmcblk0p2 /mnt/root_opios
+sudo mkdir -p /mnt/root_opios/boot
+sudo mount /dev/mmcblk0p1 /mnt/root_opios/boot

-sudo rsync -axHAWX --info=progress2 / /mnt/root1/
+sudo rsync -axHAWX --info=progress2 / /mnt/root_opios/
 ```

 Flags: archive, stay-on-filesystem (critical — skips /proc, /sys, /dev), preserve
@ -100,34 +122,34 @@ hardlinks/ACLs/xattrs, copy whole files (faster locally).
 ### 1.6 — Bind mount virtual filesystems

 ```bash
-sudo mkdir -p /mnt/root1/{proc,sys,dev,run,tmp}
-sudo mount --bind /proc /mnt/root1/proc
-sudo mount --bind /sys /mnt/root1/sys
-sudo mount --bind /dev /mnt/root1/dev
-sudo mount --bind /run /mnt/root1/run
+sudo mkdir -p /mnt/root_opios/{proc,sys,dev,run,tmp}
+sudo mount --bind /proc /mnt/root_opios/proc
+sudo mount --bind /sys /mnt/root_opios/sys
+sudo mount --bind /dev /mnt/root_opios/dev
+sudo mount --bind /run /mnt/root_opios/run
 ```

 ### 1.7 — Update fstab

 ```bash
-sudo blkid /dev/mmcblk1p1 /dev/mmcblk1p2
+sudo blkid /dev/mmcblk0p1 /dev/mmcblk0p2
 ```

-Edit `/mnt/root1/etc/fstab`. Replace old SD card references with:
+Edit `/mnt/root_opios/etc/fstab`. Replace old SD card references with:

 ```
 UUID=<boot-UUID>  /boot  vfat  defaults,noatime  0  2
-UUID=<root1-UUID> /     ext4  defaults,noatime  0  1
+UUID=<root_opios-UUID> /     ext4  defaults,noatime  0  1
 ```

 ### 1.8 — Write extlinux.conf

 ```bash
 uname -r
-find /mnt/root1/boot -name "*.dtb" | grep orangepi-3b
+find /mnt/root_opios/boot -name "*.dtb" | grep orangepi-3b
 ```

-Create `/mnt/root1/boot/extlinux/extlinux.conf`:
+Create `/mnt/root_opios/boot/extlinux/extlinux.conf`:

 ```
 TIMEOUT 10
@ -138,7 +160,7 @@ LABEL orangepi-os
    LINUX /vmlinuz-<kernel-version>
    INITRD /initrd.img-<kernel-version>
    FDT /dtbs/rockchip/rk3566-orangepi-3b.dtb
-    APPEND root=UUID=<root1-UUID> rootwait console=ttyS2,115200 console=tty1
+    APPEND root=UUID=<root_opios-UUID> rootwait console=ttyS2,115200 console=tty1
 ```

 ### 1.9 — Install u-boot to eMMC hardware boot partition
@ -152,26 +174,26 @@ find / -name "idbloader.img" -o -name "u-boot.itb" -o -name "*loader*" 2>/dev/nu
 If files exist at known paths, use them. If not, extract from SD card:

 ```bash
-sudo dd if=/dev/mmcblk0 of=idbloader.img bs=512 count=16384
-sudo dd if=/dev/mmcblk0 of=u-boot.itb bs=512 skip=16384 count=8192
+sudo dd if=/dev/mmcblk1 of=idbloader.img bs=512 count=16384
+sudo dd if=/dev/mmcblk1 of=u-boot.itb bs=512 skip=16384 count=8192
 ```

 Write to eMMC hardware boot partition:

 ```bash
-echo 0 | sudo tee /sys/block/mmcblk1/force_ro
-sudo mmc bootpart enable 1 1 /dev/mmcblk1
-sudo dd if=idbloader.img of=/dev/mmcblk1boot0 bs=512 seek=64
-sudo dd if=u-boot.itb of=/dev/mmcblk1boot0 bs=512 seek=16384
+echo 0 | sudo tee /sys/block/mmcblk0/force_ro
+sudo mmc bootpart enable 1 1 /dev/mmcblk0
+sudo dd if=idbloader.img of=/dev/mmcblk0boot0 bs=512 seek=64
+sudo dd if=u-boot.itb of=/dev/mmcblk0boot0 bs=512 seek=16384
 sudo sync
 ```

 ### 1.10 — Clean up and test

 ```bash
-sudo umount /mnt/root1/boot
-sudo umount /mnt/root1/proc /mnt/root1/sys /mnt/root1/dev /mnt/root1/run
-sudo umount /mnt/root1
+sudo umount /mnt/root_opios/boot
+sudo umount /mnt/root_opios/proc /mnt/root_opios/sys /mnt/root_opios/dev /mnt/root_opios/run
+sudo umount /mnt/root_opios
 sudo sync
 sudo poweroff
 ```
@ -189,11 +211,11 @@ Remove SD card. Power on. u-boot logo → boot menu → Orange Pi OS from eMMC.

 ## Step 2: Install Armbian

-(To be documented — Armbian rootfs goes into root2, kernel+DTB added to shared /boot, next LABEL added to extlinux.conf.)
+(To be documented — Armbian rootfs goes into root_armbian, kernel+DTB added to shared /boot, next LABEL added to extlinux.conf.)

 ## Step 3: Install NixOS

-(To be documented — NixOS rootfs goes into root3. Likely the trickiest since NixOS generates its own /boot structure.)
+(To be documented — NixOS rootfs goes into root_nixos. Likely the trickiest since NixOS generates its own /boot structure.)

 ## Reference