ASUS RT-AC42U OpenWrt Firmware
- CPU
- Qualcomm Atheros IPQ4019
- RAM
- 256 MB
- Flash
- 128NAND MB
The ASUS RT-AC42U is supported by OpenWrt/ImmortalWrt on the ipq40xx/generic target. 4 firmware images are available from the official OpenWrt 25.12.5 and ImmortalWrt 25.12.1 stable releases — download one below, or build a custom OpenWrt image for this device with your own package selection.
Specs
Specifications
| CPU | Qualcomm Atheros IPQ4019 |
|---|---|
| CPU cores | 4 |
| CPU frequency | 717 MHz |
| RAM | 256 MB |
| Flash | 128NAND MB |
| 1 Gbit Ethernet ports | 5 |
| WLAN hardware | Qualcomm Atheros IPQ4019, Qualcomm Atheros QCA9984 |
| Switch | Qualcomm Atheros QCA8075 |
Hardware data from the OpenWrt Table of Hardware; verify against your unit before flashing.
Build matrix
Supported firmware versions
| Distribution | Version | Target | Profile |
|---|---|---|---|
| OpenWrt | 25.12.5 | ipq40xx/generic | asus_rt-ac42u |
| ImmortalWrt | 25.12.1 | ipq40xx/generic | asus_rt-ac42u |
Downloads
Download images
OpenWrt 25.12.5 · ipq40xx/generic
| Image | Type | sha256 |
|---|---|---|
| openwrt-25.12.5-ipq40xx-generic-asus_rt-ac42u-initramfs-uImage.itb Minimal kernel image, useful for first install or recovery. | kernel | 59eccfcbe67c… |
| openwrt-25.12.5-ipq40xx-generic-asus_rt-ac42u-squashfs-sysupgrade.bin Not sure? Pick this if upgrading from OpenWrt. | sysupgrade | e7b5db2205d3… |
ImmortalWrt 25.12.1 · ipq40xx/generic
| Image | Type | sha256 |
|---|---|---|
| immortalwrt-25.12.1-ipq40xx-generic-asus_rt-ac42u-squashfs-sysupgrade.bin Not sure? Pick this if upgrading from OpenWrt. | sysupgrade | 6b24579f3287… |
| immortalwrt-25.12.1-ipq40xx-generic-asus_rt-ac42u-initramfs-uImage.itb Minimal kernel image, useful for first install or recovery. | kernel | 9837c53fe864… |
Downloads are served by the official OpenWrt/ImmortalWrt mirrors — unchanged upstream stable builds.
Packages & install
Default packages & installation
Default packages
Every image for the ASUS RT-AC42U ships these packages by default. The customize option below lets you add or remove packages before the image is assembled.
OpenWrt 25.12.5 · ipq40xx/generic
Device packages (2)
ath10k-firmware-qca9984-ct kmod-usb-ledtrig-usbport
Target default packages (34)
apk-mbedtls ath10k-board-qca4019 ath10k-firmware-qca4019-ct base-files ca-bundle dnsmasq dropbear firewall4 fstools kmod-ath10k-ct kmod-gpio-button-hotplug kmod-leds-gpio kmod-nft-offload kmod-usb-dwc3 kmod-usb-dwc3-qcom kmod-usb3 libc libgcc libustream-mbedtls logd mtd netifd nftables odhcp6c odhcpd-ipv6only ppp ppp-mod-pppoe procd-ujail uboot-envtools uci uclient-fetch urandom-seed urngd wpad-basic-mbedtls
ImmortalWrt 25.12.1 · ipq40xx/generic
Device packages (2)
ath10k-firmware-qca9984-ct kmod-usb-ledtrig-usbport
Target default packages (41)
apk-openssl ath10k-board-qca4019 ath10k-firmware-qca4019-ct autocore automount base-files block-mount ca-bundle default-settings-chn dnsmasq-full dropbear firewall4 fstools kmod-ath10k-ct kmod-gpio-button-hotplug kmod-leds-gpio kmod-nf-nathelper kmod-nft-offload kmod-usb-dwc3 kmod-usb-dwc3-qcom kmod-usb3 libc libgcc libustream-openssl logd luci luci-app-cpufreq mtd netifd nftables odhcp6c odhcpd-ipv6only ppp ppp-mod-pppoe procd-ujail uboot-envtools uci uclient-fetch urandom-seed urngd wpad-openssl
Installation notes
- Already running OpenWrt or ImmortalWrt: flash the sysupgrade image from LuCI (System → Backup / Flash Firmware) or with the sysupgrade command.
- The kernel / initramfs image boots from RAM without writing to flash — useful for a first install or for recovering from a failed flash.
- Verify your download against the published checksum before flashing:
$ sha256sum openwrt-25.12.5-ipq40xx-generic-asus_rt-ac42u-initramfs-uImage.itb 59eccfcbe67c2a362443fe6a9010b5ddcc02e3469ce0938821bd03094ca78c4a openwrt-25.12.5-ipq40xx-generic-asus_rt-ac42u-initramfs-uImage.itb
Build custom firmware
Need more than the default image for the ASUS RT-AC42U? Pick your packages — LuCI apps, themes, VPN clients — set the basics, and get a ready-to-flash OpenWrt image assembled from official packages in minutes.
Customize firmware for this deviceRelated
Related devices
More ASUS devices
- ASUS 4G-AX56 OpenWrt firmware
- ASUS GT-AC5300 OpenWrt firmware
- ASUS Lyra (MAP-AC2200) OpenWrt firmware
- ASUS Lyra Mini (MAP-AC1300) OpenWrt firmware
- ASUS OnHub SRT-AC1900 OpenWrt firmware
- ASUS PL-AC56 A1 OpenWrt firmware
- ASUS RP-AC51 OpenWrt firmware
- ASUS RP-AC56 OpenWrt firmware
More devices on ipq40xx/generic
Upstream
Upstream & source
- downloads.openwrt.org — ipq40xx/generic 25.12.5
- downloads.immortalwrt.org — ipq40xx/generic 25.12.1
- OpenWrt Table of Hardware
Images are assembled from packages compiled and published by the upstream OpenWrt and ImmortalWrt projects. The complete corresponding source code is available from those projects under the GPL.