Root Un-rooting help :(

[KarlosTheJackal]

Trying to un-root my UK G1 back to stock 1.6 & having some problems

Im following this guide:
Al's G1 Guide: Removing root and installing donut (UK and EU guide)

Ive got down to the part where it says download the RC8 & Put it on the Micro SD card named update

I boot to the the update & i slect "Alt+s apply sdcard:update.zip" And then the trouble starts, Ill type out what it says:

Installing from sdcard...
Finding update package...
opening update package...
Verifying update package...
Installing update...
E:Failure at line 2:
asser file_contains("SYSTEM:build.pop", "ro.build.fingerprint=tmobile/kila/dream/trout:1.5/CRC1/150275:user/ota-rel-keys,release-keys") == "true" || file_contains("SYSTEM.build.prop", "ro.build.fingerprint=tmobile/kila/dream/trout:1Installation aborted.

Press Home+Back to reboot

Help

 

[KarlosTheJackal]

Nevermind, I was using the wrong file! opps haha