JetPack 6.2.2 Flash Troubleshooting: AMD USB Incompatibility and the chroot Solution

Problem

Flashing JetPack 6.2.2 (L4T R36.5.0) onto a Jetson AGX Orin 64GB Developer Kit fails at the tegrarcm_v2 stage with ERROR: might be timeout in USB write on an AMD B650-based host PC. This happens regardless of the host OS environment (Windows WSL2, Ubuntu Live Boot, Ubuntu native install).

[ 0.2574 ] Sending bct_br
[ 0.2576 ] ERROR: might be timeout in USB write.
Error: Return value 3
Command tegrarcm_v2 --new_session --chip 0x23 ...

Background

The target setup was a real-time voice chat demo (LlamaSpeak) running on-device. The board arrived pre-flashed with JetPack 5.1.3 (CUDA 11.4), and text-based LLM inference (Llama 3 8B via MLC) was already working. However, every available ASR path required JetPack 6.

This made a JetPack 6 reflash mandatory.

Environment

Host PC (AMD, fails)

• AMD B650 AORUS ELITE V2
• RTX 4060 Ti
• USB 3.x ports (AMD USB controller)

Host PC (Intel, works)

• Samsung NT930SBE laptop
• Intel Core i5-8265U
• 8GB RAM, USB-C only (3 ports)

Target

• Jetson AGX Orin 64GB Developer Kit
• eMMC + 1TB NVMe
• Original USB-A to C data cable

Root Cause: AMD USB Controller Incompatibility

NVIDIA’s tegrarcm_v2 tool communicates with the Jetson in APX recovery mode over USB. On the AMD B650 USB controller, this communication fails at the very first stage (Sending bct_br) with a write timeout.

The following environments were tested on the AMD host, and all produced the identical error.

Mitigations attempted (all ineffective):

• Disabling USB autosuspend: echo -1 > /sys/module/usbcore/parameters/autosuspend
• Different USB ports (front/rear)
• Zadig driver replacement (VBoxUSB → WinUSB)
• Different host OS environments

The common denominator was the AMD USB controller. Switching to an Intel-based host eliminated the USB timeout entirely, and tegrarcm_v2 completed with zero errors on the first attempt.

Partial Flash Consequences

Before the root cause was identified, one flash.sh run on the AMD host partially completed. The result:

• CLI boot worked (tty2 login functional)
• Internet connectivity intact
• nvidia kernel modules loaded
• dpkg showed L4T 36.5.0 packages installed
• GUI completely broken: black screen after the NVIDIA logo
• /dev/nvhost* missing: zero GPU device nodes
• Xorg: eglInitialize() failed, no screens found
• Weston: NvRmMemInitNvmap failed with Permission denied

The root cause was an incomplete Device Tree Blob (DTB) due to a corrupted USB transfer. This is not recoverable through software: no amount of xorg.conf editing, package reinstallation, or ldconfig configuration will fix missing device tree entries. The only fix is a clean reflash with reliable USB transfer.

flash.sh reporting success does not guarantee a clean flash. USB transmission errors can silently corrupt firmware/DTB. Always verify /dev/nvhost* presence after flashing.

Solution: Intel Host + chroot

The Intel laptop had only 8GB RAM and could not boot from the external SSD via BIOS. This introduced two additional problems that had to be solved.

1. RAM exhaustion: flash.sh builds a ~6GB system.img in memory. With the Ubuntu GUI running in Live Boot, 8GB RAM is insufficient, so a segfault occurs during sed operations on the rootfs.
2. SQUASHFS corruption: Ubuntu Live Boot loads system binaries from a SQUASHFS filesystem on the USB stick. Under heavy I/O, the USB stick degraded, producing read errors, and a segfault occurred when loading sed, bash, and so on.

Failed Intermediate Approaches

Working Approach: CLI Boot + chroot

The solution was to use the USB stick only as a minimal bootstrap, then chroot into a full Ubuntu installation on the external SSD. Inside the chroot, all binaries load from the SSD, completely bypassing the USB stick’s SQUASHFS.

Step 1: Boot into CLI mode

At the GRUB menu, press e to edit the boot entry. Append systemd.unit=multi-user.target to the end of the linux line.

linux /casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash --- systemd.unit=multi-user.target

Press F10 to boot. Log in with ubuntu (no password).

Step 2: Mount SSD and enter chroot

sudo -i
mount -o rw /dev/sda1 /mnt
mount --bind /dev /mnt/dev
mount --bind /proc /mnt/proc
mount --bind /sys /mnt/sys
mount --bind /run /mnt/run
chroot /mnt /bin/bash
export PATH=/usr/bin:/usr/sbin:/bin:/sbin

Step 3: Configure networking

WiFi must be configured outside the chroot (NetworkManager runs on the host).

# Exit chroot
exit

# Connect WiFi
nmcli dev wifi connect <BSSID> password "<password>"

# Re-enter chroot
chroot /mnt /bin/bash
export PATH=/usr/bin:/usr/sbin:/bin:/sbin
echo "nameserver 8.8.8.8" > /etc/resolv.conf

Step 4: Install dependencies

apt-get update && apt-get install -y libxml2-utils binutils

Both are required by flash.sh: xmllint for XML validation and strings for binary inspection.

Step 5: Flash

Put the Jetson in recovery mode (unplug power → hold the middle Force Recovery button → plug power → wait 10s → release). Connect the USB cable, then run:

cd /home/<user>/nvidia/nvidia_sdk/JetPack_6.2.2_Linux_JETSON_AGX_ORIN_TARGETS/Linux_for_Tegra/
./flash.sh jetson-agx-orin-devkit internal

The internal flag targets eMMC, preserving any data on NVMe.

Result

[ 913.6337 ] Flashing completed
[ 913.6338 ] Coldbooting the device
*** The target generic has been flashed successfully. ***

All 60 partitions written at 100%. After rebooting the Jetson:

• Ubuntu GUI: functional
• /dev/nvhost*: 15+ device nodes present
• nvidia-smi inside Docker: Driver 540.5.0, CUDA 12.6

Post-Flash Setup

# Install JetPack SDK components
sudo apt update && sudo apt install -y nvidia-jetpack

# Verify CUDA
export PATH=/usr/local/cuda/bin:$PATH
nvcc --version  # Should show CUDA 12.6

# Mount NVMe (if applicable)
sudo mkdir -p /mnt/nvme
sudo mount /dev/nvme0n1p1 /mnt/nvme
echo "/dev/nvme0n1p1 /mnt/nvme ext4 defaults 0 2" | sudo tee -a /etc/fstab

# Docker setup with NVMe storage
sudo apt install -y docker.io nvidia-container-toolkit
sudo tee /etc/docker/daemon.json << 'EOF'
{
  "data-root": "/mnt/nvme/docker",
  "default-runtime": "nvidia",
  "runtimes": {
    "nvidia": {
      "path": "nvidia-container-runtime",
      "runtimeArgs": []
    }
  }
}
EOF
sudo systemctl restart docker

# Verify Docker + GPU
sudo docker run --rm --runtime nvidia nvidia/cuda:12.6.0-base-ubuntu22.04 nvidia-smi

Summary

References

• NVIDIA SDK Manager Install Guide
• JetPack Installation Guide
• LlamaSpeak Tutorial
• NVIDIA Developer Forum, Jetson AGX Orin
• Forum Post: USB Timeout on Flash