How to Install Cyanogenmod 7.0 on a HTC-Legend (running stock froyo)

Installing custom ROMs on a HTC Legend device running Android 2.2.x is a real pain but it can be done.
You'll need:

A HTC Legend running HTCs Froyo (Android 2.2) image
Some PC running Windows (sorry!) [you also need to install the android SDK]
Some leaked HTC Software (google)
2 Micro SD-Cards (using one would work, but having two makes it easier

Some Notes

This will void your warranty
Blabla.. insert standard disclaimer here
I didn't do any of the fancy stuff: this is just a collection of various how-tos
This will WIPE your phone! Create a BACKUP before starting!

Step 1: Temproot your Legend

First you need to gain root access in order to trick the (leaked?) HTC-Flasher. This one is easy:
Just download and install Visionary r14 and tap 'Temproot now'. Now connect your phone to a PC with the android SDK installed and start 'adb shell'. Type 'su' in the android shell and confirm the 'su' request on your phones screen.

Step 1.1: Create a Goldcard

This would be the perfect time to create a 'goldcard': Just insert the smallest micro-sd you've got (1GB is fine) and unmount it in the 'Preferences' menu. Then run (on your phone!)

# on your phone
cat /sys/class/mmc_host/mmc0/mmc0:*/cid

Copy this text into the box at http://hexrev.soaa.me/, then go to http://psas.revskills.de/?q=goldcard to receive your goldcard image via e-mail.
Now run

# on your PC
adb push goldcard.img /data/local

and type

# on your phone - make sure that the sdcard is still NOT mounted!
cat /data/local/goldcard.img > /dev/block/mmcblk0
sync
exit

Great: You've just created your first goldcard!

Step 1.2: Trick the HTC-Updater

It's time to flash some parts of your phone with some randomly downloaded software found on rapidshare and other 'grey' places (yeah!).
Search google for hack4legend-v5.zip (md5sum: b07c27cdb625f8be12d31e5e933f1eb2) and extract it: You'll only need misc1-2.img and flash_image. Upload both to your phone via

# on your PC
adb push flash_image /data/local/
adb push misc1-2.img /data/local/

and run

# on your phone - Make sure that your SD-Card is MOUNTED to do create misc_backup.img
chmod 755 /data/local/flash_image
cat /dev/mtd/mtd0 > /sdcard/misc_backup.img # (optional) create a backup of your misc partition
chmod 777 /dev/mtd/mtd0 # don't know if this is needed , but won' hurt
/data/local/flash_image misc /data/local/misc1-2.img
exit

Step 2: Downgrade from Android 2.2 to 2.1

Search Google for

RUU_Legend_HTC_WWE_1.31.405.5_R_Radio_47.26.35.04_7.05.35.26L_release_126592_signed.exe (md5sum: 59b9a33a9868a5c90a237b4f277ded6b)
HTCSync.exe (Version 2.0.33 - md5sum: 6b6573516c0007e9708ca8a1ad51f27d)
r4-legend-root.zip (md5sum: 6154a24e21df9fb6f542834f76e0d8f9)

and install HTCSync.exe. After this you can connect your phone and run RUU_Legend... : You should now be able to downgrade your phone to 2.1!

Step 3: Rooting 2.1

After rebooting into 2.1 you are ready to root your new installation: The steps to do this are documented at http://theunlockr.com/2010/06/07/how-to-root-the-htc-legend/ and http://android.modaco.com/content/htc-legend-legend-modaco-com/307487/24-may-r4-htc-legend-rooting-guide-now-with-1-31-x/

Step 4: Flashing CM7

This is documented at http://wiki.cyanogenmod.com/index.php?title=HTC_Legend:_Full_Update_Guide#Flashing_CyanogenMod
Some notes:

7.0-RC2 seems to be somewhat broken - using a nightly build (i'm using cm_legend_full-25.zip) is recommended
I'm using gapps from gapps-gb-20110307-signed.zip

Step 5: Fixing stuff

After the upgrade GPS was broken: Upgrading to a newer Radio image fixed this (i was at 47.26.35.04U-7.05.35.26L).
Use your google-fu to search for Radio_47.39.35.09_7.13.35.05.zip (md5sum = e1259d1e33c4f4cd1a747961f36d06b1) and install it via the recovery menu