FastFlowLM environment (Ubuntu 24.04 + XDNA2)

This page installs FastFlowLM (flm) and the XDNA2 NPU driver on Ubuntu 24.04 so later chapters can flm pull / flm serve without Lemonade. Hardware: XDNA2. Troubleshooting: NPU troubleshooting.

Prerequisite: the machine is XDNA2 (Strix Halo / Kraken / Strix Point / Gorgon).

Official docs: FastFlowLM Linux · Lemonade Linux + FLM (same driver source; this page uses flm only)

---

Validated baseline (2026-09-16)

Item	Value
flm	1.0.5 (/usr/bin/flm)
XRT	libxrt-npu2 2.25.0
Driver	amdxdna-dkms
Device	/dev/accel/accel0, group render
Firmware	1.1.2.65
IOMMU	amd_iommu=on iommu=pt
memlock	unlimited
Groups	render video
Validated weights	gemma4-it:e4b · qwen3.6-moe:35b-a3b

Install the latest .deb from FastFlowLM Releases; you do not have to pin 1.0.5.

---

1. Install driver and FLM

sudo add-apt-repository -y ppa:lemonade-team/stable
sudo apt update
sudo apt install -y libxrt-npu2 amdxdna-dkms

Download the matching .deb (Ubuntu 24.04 → ubuntu24.04):

sudo apt install ./fastflowlm*_ubuntu24.04_amd64.deb
sudo reboot

Reboot is required so DKMS and 1.1 firmware take effect. Do not swap firmware without the matching DKMS driver.

---

2. IOMMU

tr ' ' '\n' < /proc/cmdline | grep iommu

You need both amd_iommu=on and iommu=pt. Otherwise flm hits SVA bind -19. If missing, add them to GRUB_CMDLINE_LINUX_DEFAULT, then:

sudo update-grub
sudo reboot

⚠️ Some “large GTT” recipes set amd_iommu=off, which is incompatible with NPU.

---

3. Permissions and memlock

sudo usermod -aG render,video "$USER"   # once; re-login

ulimit -l must be unlimited. If not, add to /etc/security/limits.conf:

*    soft    memlock    unlimited
*    hard    memlock    unlimited

Re-login, then:

ls -l /dev/accel/accel0
ulimit -l

---

4. Validate

Clear ROCm userspace paths before every flm invocation:

unset ROCM_PATH HIP_PATH LD_LIBRARY_PATH
flm validate
flm list --filter installed

Expected flm validate output includes /dev/accel/accel0, firmware 1.1.x, and unlimited memlock.

Optional:

unset ROCM_PATH HIP_PATH LD_LIBRARY_PATH
bash src/npu/scripts/check_flm_npu.sh

source /opt/rocm then flm typically becomes No such device with index '0'.

---

5. Ports and exclusivity

Item	Value
flm serve	this tutorial uses 8219
Concurrent LLMs	1 on NPU
vs Lemonade	lemonade unload before flm serve if Lemonade loaded an FLM model

Next: Gemma 4 FastFlowLM · Qwen3.6 FastFlowLM · Lemonade environment