私のThinkpad P1 gen4にはFoxconn Snapdragon X55 WWANモデムがあります。私はArch（6.7.2-arch1-1）とGnome（45.3）を実行しています。
モデムファームウェアをT99W175.F0.1.0.0.9.TF.008.079にアップデートしました。また、FCCのロック解除をシンボリックリンクしました。モデムが動作していて接続して使えます。
$ ls -la /etc/ModemManager/fcc-unlock.d
lrwxrwxrwx 1 root root 56 22. Jan 22:20 105b:e0ab -> /usr/share/ModemManager/fcc-unlock.available.d/105b:e0ab
ただし、何らかの理由で接続が失われ、モデムが失われ、新しいデバイスID（+ 1）が返されます。
ログには、作業中に10〜20秒ごとに以下が表示されます。
Jan 30 08:27:31 thinkpad kernel: sequence number glitch prev=7 curr=0
....死んだ場合：
Jan 30 13:18:51 thinkpad kernel: mhi-pci-generic 0000:08:00.0: firmware crashed (6)
Jan 30 13:18:51 thinkpad kernel: wwan0: Failed to queue TX buf (-5)
Jan 30 13:18:52 thinkpad ModemManager[1372]: <msg> [modem1] port 'wwan0mbim0' no longer controllable, reprobing
Jan 30 13:18:52 thinkpad NetworkManager[1300]: <info> [1706617132.0900] device (wwan0mbim0): state change: activated -> unmanaged (reason 'removed', sys-iface-state: 'removed')
Jan 30 13:18:52 thinkpad kernel: wwan wwan0: port wwan0qcdm0 disconnected
Jan 30 13:18:52 thinkpad kernel: wwan wwan0: port wwan0mbim0 disconnected
Jan 30 13:18:52 thinkpad kernel: wwan wwan0: port wwan0at0 disconnected
Jan 30 13:18:52 thinkpad ModemManager[1372]: <wrn> [/dev/wwan0mbim0] MBIM error: Device must be open to send commands
Jan 30 13:18:52 thinkpad ModemManager[1372]: <wrn> [/dev/wwan0mbim0] MBIM error: Device must be open to send commands
Jan 30 13:18:52 thinkpad ModemManager[1372]: <wrn> [/dev/wwan0mbim0] MBIM error: Device must be open to send commands
Jan 30 13:18:52 thinkpad ModemManager[1372]: <wrn> [/dev/wwan0mbim0] MBIM error: Device must be open to send commands
Jan 30 13:18:52 thinkpad ModemManager[1372]: <wrn> [/dev/wwan0mbim0] MBIM error: Device must be open to send commands
Jan 30 13:18:52 thinkpad ModemManager[1372]: <wrn> [modem1/wwan0mbim0/mbim] Couldn't properly close QMI device: Device must be open to send commands
Jan 30 13:18:52 thinkpad passimd[2919]: resetting Passim-D3AC
Jan 30 13:18:52 thinkpad passimd[2919]: Emitting PropertyChanged('Status'='running')
Jan 30 13:18:52 thinkpad passimd[2919]: signal_name: StateChanged (is)
Jan 30 13:18:52 thinkpad ModemManager[1372]: <msg> [base-manager] port wwan0qcdm0 released by device '/sys/devices/pci0000:00/0000:00:1c.4/0000:08:00.0'
Jan 30 13:18:52 thinkpad ModemManager[1372]: <msg> [base-manager] port wwan0mbim0 released by device '/sys/devices/pci0000:00/0000:00:1c.4/0000:08:00.0'
Jan 30 13:18:52 thinkpad ModemManager[1372]: <msg> [base-manager] port wwan0at0 released by device '/sys/devices/pci0000:00/0000:00:1c.4/0000:08:00.0'
Jan 30 13:18:52 thinkpad ModemManager[1372]: <msg> [base-manager] port wwan0 released by device '/sys/devices/pci0000:00/0000:00:1c.4/0000:08:00.0'
Jan 30 13:18:52 thinkpad dnsmasq[1523]: no servers found in /etc/resolv.conf, will retry
Jan 30 13:18:52 thinkpad NetworkManager[1300]: <info> [1706617132.1380] manager: NetworkManager state is now CONNECTED_LOCAL
Jan 30 13:18:52 thinkpad NetworkManager[1300]: <warn> [1706617132.1388] modem-broadband[wwan0mbim0]: failed to disconnect modem: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: Object does not exist at path “/org/freedesktop/ModemManager1/Modem/1”
Jan 30 13:18:52 thinkpad evolution[3665]: Network disconnected. Forced offline.
Jan 30 13:18:52 thinkpad systemd[1]: Starting Network Manager Script Dispatcher Service...
Jan 30 13:18:52 thinkpad systemd[1]: Started Network Manager Script Dispatcher Service.
Jan 30 13:18:52 thinkpad kernel: wwan wwan0: port wwan0qcdm0 attached
Jan 30 13:18:52 thinkpad kernel: wwan wwan0: port wwan0mbim0 attached
Jan 30 13:18:52 thinkpad kernel: wwan wwan0: port wwan0at0 attached
Jan 30 13:18:52 thinkpad vivaldi-stable.desktop[2939]: Fontconfig error: Cannot load default config file: No such file: (null)
Jan 30 13:18:53 thinkpad passimd[2919]: signal_name: StateChanged (is)
Jan 30 13:18:54 thinkpad ModemManager[1372]: <msg> [wwan0mbim0/mbim] MBIM device is not QMI capable
Jan 30 13:18:56 thinkpad ModemManager[1372]: <msg> [device /sys/devices/pci0000:00/0000:00:1c.4/0000:08:00.0] creating modem with plugin 'foxconn' and '4' ports
Jan 30 13:18:56 thinkpad ModemManager[1372]: <msg> [base-manager] modem for device '/sys/devices/pci0000:00/0000:00:1c.4/0000:08:00.0' successfully created
Jan 30 13:18:56 thinkpad ModemManager[1372]: <msg> [modem2/wwan0mbim0/mbim] MBIM device is QMI capable
Jan 30 13:18:56 thinkpad ModemManager[1372]: <msg> [modem2] state changed (unknown -> disabled)
Jan 30 13:18:56 thinkpad NetworkManager[1300]: <info> [1706617136.5651] manager: (wwan0mbim0): new Broadband device (/org/freedesktop/NetworkManager/Devices/8)
Jan 30 13:18:56 thinkpad NetworkManager[1300]: <info> [1706617136.5655] device (wwan0mbim0): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external')
Jan 30 13:18:56 thinkpad NetworkManager[1300]: <info> [1706617136.5660] device (wwan0mbim0): modem state 'enabling'
Jan 30 13:18:56 thinkpad NetworkManager[1300]: <info> [1706617136.5666] device (wwan0mbim0): state change: unavailable -> disconnected (reason 'none', sys-iface-state: 'managed')
5Gを使わずにカードを3g+4Gに設定してみましたが、やはり役に立ちませんでした。
この問題を解決する方法についてのアイデアはありますか？