So I did the following.
I know the phone is rooted but I cant get the WIFI tether to work with 2.1. So I want to flash a new ROM. (the Vanilla one). When I try to reboot into the recovery partition using "adb shell reboot recovery" from the cmd prompt. All I get is the droid with a hazard sign. How do I fix thisIII. Flash a Custom Recovery Image on the Droid Eris
1. Download the Flash_Image file and Amon Ra’s recovery image and save them both to the tools folder of your AndroidSDK you downloaded for the How To Setup ADB procedure.
Flash_Image
Amon Ra’s Recovery Image
2. Then plug in your phone via usb cable and goto Settings >
> Development and make sure USB Debugging is checked on.
3. Open the command prompt on your computer and type in the following with hitting enter at the end of each line:
adb shell mount -o rw,remount /dev/block/mtdblock3 /system
adb push recovery-ra-eris.img /sdcard
adb push flash_image /system/bin
adb shell chmod 755 /system/bin/flash_image
adb shell flash_image recovery /sdcard/recovery-ra-eris.img
4. Close the cmd prompt and turn off you phone.
IV. Flash a Custom ROM Using the Recovery Image
1. Turn the phone on by holding down Volume Up and Power and keep holding it until the recovery screen comes up.