Asus RT-AC56U OpenWrt does not have 5GHz Wi-Fi interface

Installing and Using OpenWrt Network and Wireless Configuration
1

New to OpenWrt.
Installed latest v19.07.4 to Asus RT-AC56U, then found there is no 5G Wi-Fi interface available, only 2.4Ghz Wi-Fi there , any suggestion ?
Also, there is no Ethernet port 1 to port 4 LED lit on.

2

This https://openwrt.org/toh/asus/rt-ac56u with

Devices with Broadcom WiFi chipsets have limited OpenWrt supportability (due to limited FLOSS driver availability for Broadcom chips).

and leads to:
https://openwrt.org/meta/infobox/broadcom_wifi with

Limited means: 2.4GHz only b/g available, and 5GHz doesn't work at all. There might be some exceptions, but the general rule is as written before.

So, the practical suggestion is that if you want to use OpenWrt for wifi, buy a router without a Broadcom wifi. Sad for you, but true.

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3

This unit is Broadcom SoC , and comes two Broadcom BCM4352, Broadcom BCM43217 WLAN chips inside..
First time heard openwrt is not friend with Broadcom..
other third party rom's most favor chip-set is Broadcom such as dd-wrt

4

From the same page:

  • Broadcom has not released any FOSS drivers. Broadcom doesn’t support open-source much at all.
  • DD-WRT has a license agreement and NDA in place with Broadcom that allow usage of better, proprietary, closed source wireless drivers (binary blobs) which they are not allowed to redistribute freely.
  • OpenWrt use only FOSS drivers. Fully open-source support for Broadcom wifi chips is very limited.
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5

Thanks for the information .
which brand' drvers are FOSS ?
I may want to try x86 with Intel or Realtek WiFi chip

6

Mostly Qualcomm Atheros (ath9k for old, ath10k for new devices, ath11k for 802.11ax in future), mwlwifi (abandonware), Mediatek mt drivers.

You need to check the device page in wiki to see warnings about device/brand/driver specific issues.