OneRNG not working after reinstalling onerng_3.6-1_all.deb

[bsr]

Mark,

I booted mint 19.1 live, installed the dependencies and onerng_3.6-1_all.deb.  My onerng didn't work upon inserting and it seems modem manager is causing issues:

kernel: [ 1780.075015] usb 2-2: new full-speed USB device number 5 using xhci_hcd
kernel: [ 1780.226390] usb 2-2: New USB device found, idVendor=1d50, idProduct=6086
kernel: [ 1780.226392] usb 2-2: New USB device strings: Mfr=1, Product=3, SerialNumber=3
kernel: [ 1780.226394] usb 2-2: Product: 00
kernel: [ 1780.226395] usb 2-2: Manufacturer: Moonbase Otago http://www.moonbaseotago.com/random
kernel: [ 1780.226397] usb 2-2: SerialNumber: 00
mtp-probe: checking bus 2, device 5: "/sys/devices/pci0000:00/0000:00:14.0/usb2/2-2"
mtp-probe: bus: 2, device: 5 was not an MTP device
systemd-udevd[4774]: Process '/sbin/onerng.sh 2-2' failed with exit code 1.
kernel: [ 1780.259427] cdc_acm 2-2:1.0: ttyACM0: USB ACM device
kernel: [ 1780.259733] usbcore: registered new interface driver cdc_acm
kernel: [ 1780.259734] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
upowerd[2043]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb2/2-2
upowerd[2043]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb2/2-2/2-2:1.1
upowerd[2043]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb2/2-2/2-2:1.0
OneRNG: firmware verification failed: Invalid firmware signature
...
ModemManager[1163]: <info>  Creating modem with plugin 'Generic' and '1' ports
ModemManager[1163]: <warn>  Could not grab port (tty/ttyACM0): 'Cannot add port 'tty/ttyACM0', unhandled serial type'
ModemManager[1163]: <warn>  Couldn't create modem for device at '/sys/devices/pci0000:00/0000:00:14.0/usb2/2-2': Failed to find primary AT port

I have no use for modem manager and is known to conflict with OneRNG, so I uninstalled it and my OneRNG device does work (cat /dev/random >/dev/null causes LED dimming, etc.)  However, I still get weird errors when the device is brought up:

systemd-udevd[11215]: Process '/sbin/onerng.sh 2-2' failed with exit code 1.
upowerd[2043]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb2/2-2/2-2:1.1
upowerd[2043]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb2/2-2/2-2:1.0
upowerd[2043]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:14.0/usb2/2-2
OneRNG: firmware verification passed OK - version=3

I'm not sure why, "systemd-udevd[11215]: Process '/sbin/onerng.sh 2-2' failed with exit code 1" and I have no experience with upowerd but maybe someone else can chime in.