Raspberry Pi Model B for a Wireless AP: nl80211 driver initialization failed

Question

I'm trying to setup my Raspberry Pi Model B to act as a standalone Wireless AP using a Ralink MT7601U Wireless Adapter. However, starting hostapd presents me with this error.

pi@raspberrypi:~ $ sudo hostapd /etc/hostapd/hostapd.conf  -d
random: Trying to read entropy from /dev/random
Configuration file: /etc/hostapd/hostapd.conf
nl80211: Supported cipher 00-0f-ac:1
nl80211: Supported cipher 00-0f-ac:5
nl80211: Supported cipher 00-0f-ac:2
nl80211: Supported cipher 00-0f-ac:4
nl80211: Supported cipher 00-0f-ac:10
nl80211: Supported cipher 00-0f-ac:8
nl80211: Supported cipher 00-0f-ac:9
nl80211: Using driver-based off-channel TX
nl80211: Driver-advertised extended capabilities (default) - hexdump(len=8): 00 00 00 00 00 00 00 40
nl80211: Driver-advertised extended capabilities mask (default) - hexdump(len=8): 00 00 00 00 00 00 00 40
nl80211: interface wlan0 in phy phy0
nl80211: Set mode ifindex 3 iftype 3 (AP)
nl80211: Failed to set interface 3 to mode 3: -95 (Operation not supported)
nl80211: Try mode change after setting interface down
nl80211: Set mode ifindex 3 iftype 3 (AP)
nl80211: Failed to set interface 3 to mode 3: -95 (Operation not supported)
nl80211: Interface mode change to 3 from 0 failed
nl80211: Could not configure driver mode
nl80211: deinit ifname=wlan0 disabled_11b_rates=0
nl80211: Remove monitor interface: refcount=0
netlink: Operstate: ifindex=3 linkmode=0 (kernel-control), operstate=6 (IF_OPER_UP)
nl80211: Set mode ifindex 3 iftype 2 (STATION)
nl80211 driver initialization failed.
hostapd_interface_deinit_free(0xf94cf8)
hostapd_interface_deinit_free: num_bss=1 conf->num_bss=1
hostapd_interface_deinit(0xf94cf8)
wlan0: interface state UNINITIALIZED->DISABLED
hostapd_bss_deinit: deinit bss wlan0
wlan0: AP-DISABLED 
hostapd_cleanup(hapd=0xf95a48 (wlan0))
hostapd_free_hapd_data: Interface wlan0 wasn't started
hostapd_interface_deinit_free: driver=(nil) drv_priv=(nil) -> hapd_deinit
hostapd_interface_free(0xf94cf8)
hostapd_interface_free: free hapd 0xf95a48
hostapd_cleanup_iface(0xf94cf8)
hostapd_cleanup_iface_partial(0xf94cf8)
hostapd_cleanup_iface: free iface=0xf94cf8

Here is my /etc/hostapd/hostapd.conf:

interface=wlan0
driver=nl80211
ssid=TestSSID        
hw_mode=g
channel=7
wmm_enabled=0
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0

Any help would be appreciated, and I'm happy to provide more info

Answer 1

The important messages seem to be:

nl80211: Set mode ifindex 3 iftype 3 (AP)
nl80211: Failed to set interface 3 to mode 3: -95 (Operation not supported)
nl80211: Interface mode change to 3 from 0 failed
nl80211: Could not configure driver mode

For my interpretation hostapd tries to set the interface to mode 3 (AP) that is an access point (line 1). But the driver claims Operation not supported (line 2). It seems that the Ralink MT7601U Wireless Adapter does not support an access point. Check with:

rpi ~$ iw phy phy0 info

You will get a bunch of information from the MT7601U. Just look at the section Supported interface modes:. For comparison here are the modes of my RPi 3B+:

rpi ~$ iw phy phy0 info
[..]
    Supported interface modes:
             * IBSS
             * managed
             * AP
             * P2P-client
             * P2P-GO
             * P2P-device
[..]

Here you will find mode AP.