How do I boot into recovery mode on an HTC Dream/G1?

I'm trying to revive and root an old HTC Dream. According to every ten-year-old tutorial I've been able to find, you should be able to boot into recovery mode by holding the Home + Power button as you boot the phone up. This simply doesn't work for me - the phone just boots up normally. Is there anything else I can try? Does it differ for different specific HTC Dream models, or something? It might be relevant that I've downgraded this phone down to Android 1/RC29 following tutorials. I've also noticed that the Call + Menu + Power combination to reboot the phone doesn't work, either.