Board	eMMC	Max Image	Default
ESPRESSObin v7 (no eMMC)	—	SD only	—
ESPRESSObin v7 (4GB)	4 GB	3.5 GB	Use `--size 3.5G`
ESPRESSObin v7 (8GB)	8 GB	6 GB	4 GB
ESPRESSObin Ultra	8 GB	6 GB	4 GB
MOCHAbin	8 GB	6 GB	4 GB

Notes:

Leave ~500MB-2GB free for data partition and wear leveling
For 4GB eMMC boards: build with --size 3.5G
MOCHAbin can use SATA/NVMe for larger installations
gzwrite requires RAM to decompress (~350MB buffer)

Prerequisites

Serial console adapter (USB-TTL)
USB drive or SD card with the image
Serial terminal: screen, minicom, or PuTTY

Serial Console Settings

Baud rate:    115200
Data bits:    8
Parity:       None
Stop bits:    1
Flow control: None

# Linux
screen /dev/ttyUSB0 115200
# or
minicom -D /dev/ttyUSB0 -b 115200

Prepare Boot Media

Option A: USB Drive (Recommended)

Format a USB drive with a FAT32 or ext4 partition and copy the image:

# Download the image
wget https://github.com/CyberMind-FR/secubox-deb/releases/latest/download/secubox-espressobin-v7-bookworm.img.gz

# Mount USB drive (assuming /dev/sdb1)
sudo mount /dev/sdb1 /mnt

# Copy image
sudo cp secubox-espressobin-v7-bookworm.img.gz /mnt/

# Unmount
sudo umount /mnt

Option B: SecuBox Live USB

If using a SecuBox Live USB, copy the image to the persistence partition (partition 4):

# The persistence partition is already ext4
sudo mount /dev/sdX4 /mnt
sudo cp secubox-espressobin-v7-bookworm.img.gz /mnt/
sudo umount /mnt

U-Boot Flash Procedure

1. Enter U-Boot

Connect serial console and power on the board. Press any key to stop autoboot:

Hit any key to stop autoboot:  0
=>

2. Initialize USB

=> usb reset
resetting USB...
USB XHCI 1.00
scanning bus usb@58000 for devices... 2 USB Device(s) found
scanning usb for storage devices... 1 Storage Device(s) found

3. Verify Storage

=> usb storage
  Device 0: Vendor: Kingston Rev:  Prod: DataTraveler 3.0
            Type: Removable Hard Disk
            Capacity: 29510.4 MB = 28.8 GB

4. List Files

For FAT32 partition (partition 1):

=> ls usb 0:1
       314543223 secubox-espressobin-v7-bookworm.img.gz

For ext4 partition (partition 4 on Live USB):

=> ls usb 0:4
       314543223 secubox-espressobin-v7-bookworm.img.gz

5. Flash to eMMC

# Set load address (needs ~350MB free RAM)
=> setenv loadaddr 0x1000000

# Load image from USB
# For FAT32 (partition 1):
=> load usb 0:1 $loadaddr secubox-espressobin-v7-bookworm.img.gz

# For ext4 (partition 4):
=> load usb 0:4 $loadaddr secubox-espressobin-v7-bookworm.img.gz

# Write to eMMC with automatic decompression
=> gzwrite mmc 1 $loadaddr $filesize

The gzwrite command decompresses and writes directly to eMMC. This takes 2-5 minutes depending on image size.

6. Configure Boot Order

# Set eMMC as primary boot device
=> setenv boot_targets "mmc1 mmc0 usb0"
=> saveenv
Saving Environment to SPI Flash... done

# Reboot
=> reset

Alternative: Flash from SD Card

If the image is on SD card instead of USB:

=> mmc dev 0                    # Select SD card
=> ls mmc 0:1                   # List files
=> setenv loadaddr 0x1000000
=> load mmc 0:1 $loadaddr secubox-espressobin-v7-bookworm.img.gz
=> gzwrite mmc 1 $loadaddr $filesize    # Write to eMMC

Boot Device Reference

Device	U-Boot	Description
SD Card	`mmc 0`	microSD slot
eMMC	`mmc 1`	Internal eMMC (install target)
USB	`usb 0`	USB storage
SATA	`scsi 0`	SATA drive (MOCHAbin)

Board-Specific Notes

ESPRESSObin v7

eMMC: Optional, may need to boot from SD if not present
RAM: 1GB models have limited space, use loadaddr 0x1000000
Network: eth0=WAN, lan0/lan1=LAN (DSA switch)

ESPRESSObin Ultra

eMMC: 8GB built-in
RAM: Up to 4GB
Network: Same as v7

MOCHAbin

eMMC: 8GB built-in
RAM: 4GB (can hold larger images)
Network: Multiple 10GbE + GbE ports
SATA: Can also install to SATA drive

# MOCHAbin: Flash to SATA instead of eMMC
=> scsi scan
=> gzwrite scsi 0 $loadaddr $filesize

Troubleshooting

USB Not Detected

=> usb reset
=> usb tree        # Show USB device tree
=> usb info        # Detailed USB info

eMMC Not Detected

=> mmc list        # List MMC devices
=> mmc dev 1       # Select eMMC
=> mmc info        # Show eMMC info

Load Fails (File Not Found)

=> ls usb 0        # List all partitions
=> ls usb 0:1      # Try partition 1
=> ls usb 0:2      # Try partition 2

Out of Memory

For 1GB boards, ensure no other data is loaded:

=> setenv loadaddr 0x1000000    # Use lower address

Reset Environment

=> env default -a
=> saveenv

Check Current Environment

=> print                    # Show all variables
=> print boot_targets       # Show boot order
=> print loadaddr           # Show load address

Post-Installation

After flashing, the board boots SecuBox automatically.

Default Credentials

User	Password
root	secubox
secubox	secubox

First Steps

Connect via SSH: ssh root@<IP>
Change passwords: passwd
Access Web UI: https://<IP>:8443

Network Interfaces

Board	WAN	LAN
ESPRESSObin	eth0	lan0, lan1
MOCHAbin	eth0	eth1-eth4, sfp0-sfp1

ARM Installation via U-Boot

Supported Boards

eMMC Storage Limits