Infuse-SDK is on Zephyr 4.4.0

2026-05-25

Zephyr 4.4.0 is out. Infuse-SDK is a full application stack, not a networking library, so moving a release means validating the path applications actually upgrade. The Nordic export that carries SoftDevice and LTE modem support is on nRF Connect SDK 3.3.0. Fleets that need to stay on the 4.3.0-based branch can; that tree still takes bugfixes.

4.4.0 brings NAND flash (already in the 4.3.0 Infuse tree), nRF54LM20 with an on-die NPU, a native Zephyr LoRa backend with LoRaWAN following, tighter Cortex-M switching, and a crypto split: algorithm implementations moved from MbedTLS into TF-PSA-Crypto.

Every Infuse-SDK packet is ChaCha20-Poly1305. Nordic’s Oberon acceleration is about 3× on that AEAD; we are not giving that up. After the TF-PSA-Crypto split, Zephyr 4.4.0 has no supported way for an application or module to hook acceleration without forking tf-psa-crypto. We proposed a fix upstream. Infuse-SDK already ships ChaCha20-Poly1305 and SHA acceleration on Nordic SoCs.

Over the 4.4.0 cycle Embeint merged 49 pull requests into Zephyr, including OTA from Zephyr v4.x via Trusted Firmware-M and a generic SPI NAND driver.

• Zephyr RTOS 4.4 announcement (opens in a new tab)
• Zephyr 4.4.0 release notes (opens in a new tab)
• nRF Connect SDK 3.3.0 (opens in a new tab)
• Infuse-SDK 4.3.0 branch (opens in a new tab)
• Upstream accelerator proposal (opens in a new tab)
• 49 PRs in the 4.4.0 cycle (opens in a new tab)