Just in case it helps, my system ( hp prodesk G2, ubuntu 18.04, kernel 5.13 ) got stuck at boot time until I unplugged the rtl8821cu USB dongle . UDEV rule with usb_modeswitch didn't help with that. This was the log:
[ 7.343567] ata2: SATA link down (SStatus 4 SControl 300)
[ 7.660504] ata3: SATA link down (SStatus 4 SControl 300)
[ 7.976400] ata4: SATA link down (SStatus 4 SControl 300)
[ 8.292375] ata5: SATA link down (SStatus 4 SControl 300)
[ 8.608524] ata6: SATA link down (SStatus 4 SControl 300)
I solved this by adding a system service: /etc/systemd/system/rtl8821cu_usbmodeswitch.service
[Unit]
Description=switch rtl8812cu from disk to wifi mode
[Service]
ExecStart=/usr/src/rtl8821cu/switch_mode.sh
[Install]
WantedBy=multi-user.targetç
Just in case it helps, my system ( hp prodesk G2, ubuntu 18.04, kernel 5.13 ) got stuck at boot time until I unplugged the rtl8821cu USB dongle . UDEV rule with usb_modeswitch didn't help with that. This was the log:
[ 7.343567] ata2: SATA link down (SStatus 4 SControl 300) [ 7.660504] ata3: SATA link down (SStatus 4 SControl 300) [ 7.976400] ata4: SATA link down (SStatus 4 SControl 300) [ 8.292375] ata5: SATA link down (SStatus 4 SControl 300) [ 8.608524] ata6: SATA link down (SStatus 4 SControl 300)
I solved this by adding a system service: /etc/systemd/system/rtl8821cu_usbmodeswitch.service
[Unit] Description=switch rtl8812cu from disk to wifi mode [Service] ExecStart=/usr/src/rtl8821cu/switch_mode.sh [Install] WantedBy=multi-user.targetç
that calls the script: switch_mode.sh
!/bin/sh
( usb_modeswitch -KW -v 0bda -p 1a2b ) &