Quite simply - don't fiddle with Kies! I tried getting Kies to install the Froyo update on my Galaxy S (i live in the UK) using the registry hack that has been widely published. It didn't work and I ended up witha slightly newer version of 2.1 than I already had. Phone seemed to work fine, until I put my SIM card back in. It immediately restarted itself as soon as I tried to use 3G. I went through all the settings, everything seemed to be the same as it was before the flash, but still it restarted everytime I connected to the 3G network. Sooo, I decided to try and restore it to the previous firmware version again by changing the KIES regisrty values. Everything seemed to go well, phone downloaded the correct version, installed it fine etc and then KIES notified me that the firmware upgrade was succesful and the phone will now reboot. Only it didnt. It turned off and hasn't turned back on since It doesn't get recognised when plugged into USB, it doesn't even show a charging logo when plugged into the mains. It does get VERY warm when I leave the battery in for 10 minutes or so though. I've tried all the three button combos posted around, I've taken the battery out and in and out and in etc etc... nothing. It's a shiny 9mm thick brick now Moral of the story? Don't muck about with KIES! I'm sending it back to Samsung tomorrow btw... hopefully they'll fix it.