On Wed, Apr 06, 2005 at 03:38:58PM +0200, Schwerzmann, Stephan wrote:
> hello,
> 
>   (red-faced-and-singing-the-blues)
> 
>   I did date experiments with an U10: I set the date 
> from the unix to 2038-01-19T03:14 an let the box run 
> past the overflow...
> 
>   now the U10 won't boot anymore, not even from CD...   :-/

I presume the kernel hangs?

>   OBP is able to tell me the proper date (with ist "date" command)
> but I have difficulties to find a OBP command reference telling 
> me how to set the date to a more reasonable value (like today) 
> directly from the OBP prompt  (single command or some forth hack)
> 
>   help is appreciated...

You could do that.  ISTR that U10s use MTK48T-something NVRAM
chips like U1s and U2s.

1) Do a `show-devs' to locate the path to the nvram or eeprom 
device node.

2) Locate the path and map the device in by doing:

" <path>" map-device

3) Make a value so you don't forget where you mapped it:

value rtc-regs

4) Now you should be able to locate the clock registers
in the NVRAM by either looking at the sources or scanning
through the contents with the `dump' command.

5) You should be able to patch individual bytes by using:

<val> <addr> c!


Alternatively, you can boot a kernel with `-d' to get to DDB,
put a breakpoint at the end of clock_ymdhms_to_secs(), change
the return value in %o0 to something more appropriate, and 
use the date command to set the correct date once you get to
the prompt.

Eduardo