/dev/ttyU0 - block at open

[Ruslan Bukin]

Hi!

I am using u3g driver for Gobi 2000 QDL device.
The open ("/dev/ttyU0", O_RDWR) does not return anything,
But it returns immediately with only O_NONBLOCK or O_NDELAY flags.

is it normal behavior or not?

The device is answering for commands normally in non-block state,
but only returns error when I try to write firmware to it.

I think may be the problem is in block/non-block modes.

Thanks

-Ruslan