remount failed: Operation not permitted

[Guest subhramani]

My original problem is that I ran the OTA upgrade of Froyo the day I bought my Desire here in India. Now, I am trying to downgrade the HBOOT so that I can root my device.

Now the issue is that I am not able to follow the procedure to downgrade the HBOOT as I am unable to push the flash_image and the mtd0.img into the data folder as I get an error "remount failed: Operation not permitted" when I try to remount.

I have tried to access shell and do a 'su' which again comes up with the 'access denied' message.

Can anyone help me get rid of the access issue so that I can downgrade the HBOOT and root my device?

Thanks a lot in advance :P