docs: Add eMMC size limits for ESPRESSObin/MOCHAbin

Document storage constraints for ARM boards:
- ESPRESSObin 4GB eMMC: max 3.5GB image
- ESPRESSObin 8GB/MOCHAbin: 4GB default, 6GB max
- MOCHAbin SATA/NVMe alternative for larger installs
- Added MOCHAbin README.md with U-Boot flash guide

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

board/espressobin-v7/README.md

@@ -4,9 +4,24 @@
 
 - **SoC**: Marvell Armada 3720 (Cortex-A53 Dual-core 1.2GHz)
 - **RAM**: 1-2 GB DDR4
-- **Storage**: eMMC (optionnel) / microSD
+- **Storage**: eMMC (optional) / microSD
 - **Network**: 1x WAN GbE + 2x LAN (Marvell 88E6341 DSA switch)
-- **Profile**: SecuBox Lite (optimisé pour RAM limitée)
+- **Profile**: SecuBox Lite (optimized for limited RAM)
+
+## Storage Limits
+
+| Model | eMMC | microSD | Recommended Image |
+|-------|------|---------|-------------------|
+| ESPRESSObin v7 (no eMMC) | — | Up to 128GB | SD card boot |
+| ESPRESSObin v7 (4GB eMMC) | 4 GB | Up to 128GB | **3.5GB max** |
+| ESPRESSObin v7 (8GB eMMC) | 8 GB | Up to 128GB | 4GB default |
+| ESPRESSObin Ultra | 8 GB | Up to 128GB | 4GB default |
+
+**Important eMMC constraints:**
+- Default image size: **4GB** (fits 8GB eMMC)
+- For 4GB eMMC boards, use `--size 3.5G` when building
+- Leave ~500MB free for data partition and wear leveling
+- U-Boot `gzwrite` requires enough RAM to decompress (~350MB)
 
 ## Pre-requisites
 

board/mochabin/README.md

@@ -0,0 +1,135 @@
+# MOCHAbin — SecuBox Installation Guide
+
+## Hardware
+
+- **SoC**: Marvell Armada 7040 (Cortex-A72 Quad-core 1.8GHz)
+- **RAM**: 4 GB DDR4
+- **Storage**: 8 GB eMMC + SATA + NVMe
+- **Network**: 2x SFP+ 10GbE + 4x GbE + 10G RJ45
+- **Profile**: SecuBox Full (all features enabled)
+
+## Storage Limits
+
+| Storage | Capacity | Notes |
+|---------|----------|-------|
+| eMMC | 8 GB | Primary boot device |
+| SATA | Unlimited | Optional data storage |
+| NVMe | Unlimited | High-speed storage |
+| microSD | Up to 128GB | Backup boot option |
+
+**Image size constraints:**
+- Default image: **4GB** (fits 8GB eMMC with room for data)
+- Maximum recommended: **6GB** (leaves 2GB for data/logs)
+- SATA/NVMe can be used for `/data` partition
+
+## Installation via U-Boot
+
+### 1. Enter U-Boot
+
+Connect serial console (115200 8N1) and power on. Press any key:
+
+```
+Hit any key to stop autoboot:  0
+=>
+```
+
+### 2. Initialize USB
+
+```
+=> usb reset
+=> usb storage
+```
+
+### 3. Flash to eMMC
+
+```bash
+# Set load address (4GB RAM available)
+=> setenv loadaddr 0x1000000
+
+# Load from USB (partition 1 or 4)
+=> load usb 0:1 $loadaddr secubox-mochabin-bookworm.img.gz
+
+# Write to eMMC with decompression
+=> gzwrite mmc 1 $loadaddr $filesize
+```
+
+### 4. Configure Boot Order
+
+```bash
+=> setenv boot_targets "mmc1 scsi0 usb0 mmc0"
+=> saveenv
+=> reset
+```
+
+## Alternative: Flash to SATA
+
+For larger installations, flash to SATA drive:
+
+```bash
+=> scsi scan
+=> load usb 0:1 $loadaddr secubox-mochabin-bookworm.img.gz
+=> gzwrite scsi 0 $loadaddr $filesize
+```
+
+## Boot Device Reference
+
+| Device | U-Boot | Description |
+|--------|--------|-------------|
+| eMMC | `mmc 1` | 8GB internal (default) |
+| SD Card | `mmc 0` | microSD slot |
+| SATA | `scsi 0` | SATA drive |
+| USB | `usb 0` | USB storage |
+
+## Network Interfaces
+
+| Interface | Role | Speed |
+|-----------|------|-------|
+| eth0 | WAN | 1 Gbps |
+| eth1-eth4 | LAN | 1 Gbps |
+| eth5, eth6 | SFP+ | 10 Gbps |
+
+## Default Credentials
+
+| User | Password |
+|------|----------|
+| root | secubox |
+| secubox | secubox |
+
+## Serial Console
+
+```
+Baud rate:    115200
+Data bits:    8
+Parity:       None
+Stop bits:    1
+```
+
+```bash
+screen /dev/ttyUSB0 115200
+```
+
+## Troubleshooting
+
+### eMMC not detected
+```
+=> mmc list
+=> mmc dev 1
+=> mmc info
+```
+
+### SATA not detected
+```
+=> scsi scan
+=> scsi info
+```
+
+### Check boot environment
+```
+=> print boot_targets
+=> print fdtfile
+```
+
+## See Also
+
+- [ARM Installation Wiki](https://github.com/CyberMind-FR/secubox-deb/wiki/ARM-Installation)
+- [ESPRESSObin v7 Guide](../espressobin-v7/README.md)

wiki/ARM-Installation.md

@@ -12,6 +12,22 @@ This guide covers installing SecuBox on ARM boards (Marvell Armada) using U-Boot
 | ESPRESSObin Ultra | Armada 3720 | 1-4 GB | secubox-lite |
 | MOCHAbin | Armada 7040 | 4 GB | secubox-full |
 
+## eMMC Storage Limits
+
+| 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)