i flashed to GOT, and then update to CM6 ard..

i'll try to make a simple step-by-step tutorial:

1. backup you data
contact can be sync with your gmail. sms and setting can try Sprite Backup
for apps it is better to fresh install after flash to CM6 than backup & restore.
(my backup with Sprite can't be restore. maybe because different OS version?)
media files such as picture, mp3 and video just copy to computer, later coy back to card.

2. Vulnerable recovery hacks
follow the steps (and files) as link below
http://modmymobile.com/forums/564-motorola...e-recovery.html
RSD Lite and USB driver can get from here: http://groupoften.wordpress.com/2010/06/15/install-via-sbf/
(in my case, the long filename and file at desktop makes the RSD Lite unable to start the flashing. renaming it to recovery.sbf and put the file at C:\ fix this error)
need to rename the script that will automatically recover the ori .sbf file 1st. just use root explorer and rename this file.
/system/etc/install-recovery.sh . after flash the Vulnerable recovery , my phone will successfully reboot into Eclair. but RSD Lite wont detact it. is show need to manually reboot. i tried to reboot again manually and still same issue. i just close RSD Lite and unplug the cable after success reboot into Eclair. its just OK. i use the open recovery by skrilax_CZ


3. know your bootloader
hold UP on the keypad while boot your MS to load bootloader,
if 90.78, later, to enter recovery mode is hold X then press Power
if not 90.78, HOLD Camera button then press Power

3. Recovery Mode and making nandroid backup
follow the instruction on link below, start at step 2 as we already done step 1:
http://modmymobile.com/forums/563-motorola...-19-2010-a.html
as we are going to flash diff ROM then update with diff ROM, it is advisable to do wipe data (factory reset) when in this mode.
also advisable to do nandroid backup of your original ROM, so if bad luck when flash, you can still restore directly from your SD card.
in this mode also have the function to root and mem hack, which if needed can be done after finish update to CM6.

4. flashing to GOT
get the file here:
http://forum.xda-developers.com/showthread.php?t=810726
(i use the RETAIL EUROPE - RTEU)

flashing instruction here:
http://groupoften.wordpress.com/2010/06/15/install-via-sbf/
(again, use short filename with no space and put at C:\ to avoid any problem)

5. update to CM6
the files and instruction as below:
http://forum.xda-developers.com/showthread.php?t=784750
CM6 have a bootloop with bluetooth problem. update with this files afterward:
http://code.google.com/p/cyanogenmod4miles...10.11.03%29.zip

if you want to use Goggle apps, you also need to update another file after you update the CM6, files as below:
http://www.tap3w0rm.com/hosted/android/gap...1025-signed.zip
same as CM6 put the files in folder /sdcard/OpenRecovery/updates

while you still in recovery mode, you might want to use the root, mem hack, and overclock function.
Memhack is enable by default in CM6 (credit to scpt)
6. Congratulation!
your Milestone is now running on Froyo.
EDIT: update few of the steps.

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on my side, didn't feel Froyo is snappier than my stock Starhub Eclair. but loving the install to SD card tho, now i still have >100MB in my phone memory. ADW launcher feels lagging and harder to move to next home screen when compare with Launcherpro. uninstall ADW. Wifi still have the problem as when i using Eclair, it will DC for no apparent reason even when i'm browsing or download. you can try to clear dalvik cache when feel lagging in froyo CM6. i feel smoother now after clear dalvik cache. now i downclock to 550Mhz also smooth but using LauncherPro not ADW launcher. default 900Mhz but not smooth use ADW.