[FS#661] USB hostless modem is not detected during boot - HooToo HT-TM02 - Ramips

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - Christoph (eldi0s) 

Attached to Project - LEDE Project
Summary - USB hostless modem is not detected during boot - HooToo HT-TM02 - Ramips
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - High
Priority - Very Low
Reported Version - lede-17.01
Due in Version - Undecided
Due Date - Undecided
Details - After flashing my HooToo HT-TM02 with LEDE 17.01 I noticed that my hostless modem
ZTE MF823 is not detected when attached during boot. lsusb or cat /sys/kernel/debug/usb/devices
just shows nothing. Also dmesg is logging nothing regarding the device during boot.
If the modem is hotplugged, everything works fine. Same behaviour in OpenWRT Chaos Chalmer.

Tried unloading and reloading all usb related modules with no success. No detection at all.
Only unplugging and replugging helps. If the modem is detected after replugging, a
router reboot will detect it properly. A reboot without a forced detection via replugging leads to
no detection. Powering the router down, also results in no detection after rebooting.

If attached to a "non powered" USB-Hub it gets detected during boot, so no power issue here.

And the modem works perfekt after boot on a WD MyNet 600 with LEDE 17.01. So i think it's a
platform related issue handling the usb modules.

Hope there is enough info for someone to find the bug.

THX. 

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=661