Installed Galaxy S3 ROM on Galaxy S2 I installed a ROM meant for Galaxy S3 on my Galaxy S2 phone by mistake and now the phone won't boot.

I can get into Download Mode fine but I can't get to Recovery Mode because the ROM installed a S3 specific recovery as well.

How do I fix it?
Go to Download Mode and flash Galaxy S2 firmware/recovery using heimdall or Odin (over USB). There's no other way.