SNIP

So what you really want is programming a 24C1024. I need to say that the
way you try to achive this may be original but not effective. Besides,
pulling a line high while a transceiver pulls it low will not work. The
bus is meant to have an overiding low which can easily be concluded from
the specs. The protocol is based on it. Worst case you destroy a
transceiver.

As the 24C1024 has a I2C interface, it can be easily programmed from a
parallel printerport of an (old) PC by bitbanging. Use a PC that runs DOS
or WIN9x so you can write directly to the port. Even old GWBASIC can be
used to write the program. It's a lot of work but less then what you're
trying to do now.

petrus bitbyter

I had in mind a 220R series resistor in line with SDA from the programmer
and pulling up the 24C1024 side with the Tiny.
Anyway, original as you say, but today I found a solution... There is some
software called PonyProg that I use for something else. Whilst browsing the
..INI file, there was a variable called I2CBaseAddress, set to a default
value of 0XA0. I changed this to 0xA2 in the hope that it would set the bit
I wanted. After restarting PonyProg, sure enough, with the 24C512 device
selected, the upper block was read.
Happy ending and much effort saved.If anyone is interested in PonyProg, the
address is Lancos.com
Thanks for all the help from everyone.