Hi!
I've got 2 Huawei modems. One of them in Hi_link mode work well on older Slackwares and second did not, so I install 14.2 and 4.4.38 kernel and make initrd.
After that when I power up server, both modems stay in "mass storage" mode. When I 'modeswitch' them manually or use something like they appears as modems. After reboot (with power turn on) they remain in previous state.
Server is IBM X3650 and rebooting took long time.

I was trying to enable serial console, but for some reason serial port doesn't want to work. I turn off internal/bios management console but I still can't send/receive any data. Serial port hardware seems to work, because in "internal console" mode sends some rubbish via null modem to other terminal.
I can see port in /proc/tty/driver# cat serial

So, the question is, what should I do with udev and how, so it 'modeswitch' my modem after power on? And before rc.inet1 try to bring up interfaces?
I still have got disk with installed Slackware 14.1 without initrd and udev work there just fine.

it's 5.06.2017 and I forced my com port to work find new logs.
From /var/messages

So I fix it my self.
1) I comment initrd in lilo.conf but it wasn't help. But I keep it commented if it is not necessary.
2) Manually (from source) upgrade my usb_modeswitch (from 2.2.x to 2.5.0) . It changes usb_modeswitch in /lib/udev, among other things, and that helps.

I also add launch rc.inet1 script to /etc/udev/rules.d/70-persistent-net.rules after system install eth2 (one of Huawei modem in my case).