[beagleboard] I2C-2 - timeouts

Hello! I have problems with i2c-2... I'm using Atmel's ATAVRSBIN1
board with three I2C devices on it, all 1.8V capable, and two pullups
on it - 4K7 to 2.5V.

AFAIU, I have to disable pullups on pins of OMAP3 (to use board's
MUX_VAL(CP(I2C2_SCL), (IEN | PTU | DIS | M0)) /*I2C2_SCL*/\
MUX_VAL(CP(I2C2_SDA), (IEN | PTU | DIS | M0)) /*I2C2_SDA*/\

done, got it recompiled, place resulting u-boot.bin to fat and /boot
sections, booting ok, but still same problem:
# i2cdetect -r 2
i2c_omap i2c_omap.2: controller timed out

I read all topics here about "i2c_omap.2: controller timed out", but
all solutions is not useful. I know it's wrong condition on line, but
how to fix it and which it must be?

What kind of reason could be here?
1) wrong pullups voltage? 2.5V, but it's pull-up, no matter of which
voltage on it, or I'm wrong?
2) wrong u-boot pinmux settings?
3) I'm using unmodified kernel from Angstrom of version 2.6.32 and I
see /dev/i2c-1 2 and 3, all of them

I'm occasionally ( only once ! :frowning: ) saw 2 devices (of 3) when
i2cdetect -r 2 but second try show me timeouts again...