[Desire HD Q&A, Help & Troubleshooting] Pluisje89:
This sounds like a piece of cake, but I'm just not seeing it.

The DHD has the ClockWork Mod installed.

I did the bootloader edit to get a permanent root.

Now I want to get the stock HTC rom back on it (no root, original recovery).

I've tried the .exe RUU, but it didn't work.

Installing the rom.zip with CWM also gave an error:

Installing: SDCARD:rom.zip

Finding update package...

Opening update package...

E: Can't open /sdcard/rom.zip

(bad)

Installation aborted

What else can I do? Please don't say 'Flash the original ROM' because I don't exactly know what it means. A (moderate) step by step guide would be very, very nice.

Added log from ROM Manager:

Starting recovery on Sat Dec 25 14:08:35 2010
framebuffer: fd 4 (480 x 800)
ClockworkMod Recovery v2.5.1.3
Command: "/sbin/recovery"

ro.secure=0
ro.allow.mock.location=1
ro.debuggable=1
persist.service.adb.enable=1
ro.build.id=FRG83
ro.build.display.id=htc_ace-eng 2.2.1 FRG83 eng.koush.20101127.182301 test-keys
ro.build.version.incremental=eng.koush.20101127.182301
ro.build.version.sdk=8
ro.build.version.codename=REL
ro.build.version.release=2.2.1
ro.build.date=Sat Nov 27 18:23:28 PST 2010
ro.build.date.utc=0
ro.build.type=eng
ro.build.user=koush
ro.build.host=Koushik-OSx86.local
ro.build.tags=test-keys
ro.product.model=HTC Desire HD
ro.product.brand=generic
ro.product.name=htc_ace
ro.product.device=ace
ro.product.board=ace
ro.product.cpu.abi=armeabi-v7a
ro.product.cpu.abi2=armeabi
ro.product.manufacturer=HTC
ro.product.locale.language=en
ro.product.locale.region=US
ro.wifi.channels=
ro.board.platform=msm7x30
ro.build.product=ace
ro.build.description=htc_ace-eng 2.2.1 FRG83 eng.koush.20101127.182301 test-keys
ro.build.fingerprint=generic/htc_ace/ace/ace:2.2.1/FRG83/eng.koush.20101127.182301:eng/test-keys
ro.sf.lcd_density=240
debug.fb.rgb565=0
ro.gsm.2nd_data_retry_config=max_retries=3, 2000, 2000, 2000
rild.libpath=/system/lib/librilswitch.so
rilswitch.vendorlibpath=/system/lib/libhtc_ril.so
rilswitch.ganlibpath=/system/lib/libganril.so
ro.ril.enable.a53=1
ro.ril.enable.dtm=0
ro.ril.gprsclass=10
ro.ril.hsdpa.category=10
ro.ril.hsupa.category=6
ro.ril.hsxpa=2
ro.ril.def.agps.feature=1
ro.ril.disable.fd.plmn.prefix=23402,23410,23411
ro.ril.enable.sdr=0
ro.ril.enable.gea3=0
ro.telephony.default_network=0
wifi.interface=eth0
wifi.supplicant_scan_interval=15
mobiledata.interfaces=rmnet0,rmnet1,rmnet2
ro.opengles.version=131072
dalvik.vm.heapsize=32m
ro.ril.def.agps.mode=2
ro.ril.disable.power.collapse=1
ro.com.google.clientidbase=android-htc
ro.com.google.networklocation=1
ro.com.google.gmsversion=2.2_r7
ro.setupwizard.enable_bypass=1
dalvik.vm.lockprof.threshold=500
dalvik.vm.dexopt-flags=m=y
media.a1026.nsForVoiceRec=0
media.a1026.enableA1026=1
htc.audio.alt.enable=0
htc.audio.hac.enable=0
keyguard.no_require_sim=true
ro.config.notification_sound=pixiedust.ogg
ro.config.alarm_alert=Alarm_Beep_03.ogg
media.stagefright.enable-player=true
media.stagefright.enable-meta=true
media.stagefright.enable-scan=true
media.stagefright.enable-http=true
ro.kernel.android.checkjni=0
ro.setupwizard.mode=OPTIONAL
net.bt.name=Android
net.change=net.bt.name
dalvik.vm.stack-trace-file=/data/anr/traces.txt
ro.factorytest=0
ro.serialno=HT0AERX05218
ro.bootmode=recovery
ro.baseband=26.03.02.26_M
ro.carrier=HTC-Dutch
ro.bootloader=0.85.2007
ro.hardware=spade
ro.revision=128
ro.emmc=1
init.svc.recovery=running
init.svc.adbd=running

I:Checking for extendedcommand...
I:Running extendedcommand...
Waiting for SD Card to mount (20s)
SD Card mounted...
I:Running script:
I:
print "ROM Manager Version 3.0.0.2"
print "Preparing to install ROM..."
install_zip SDCARD:/rom.zip

Parsed /tmp/extendedcommand
calling command print
ROM Manager Version 3.0.0.2
calling command print
Preparing to install ROM...
calling command install_zip

-- Installing: SDCARD:/rom.zip
Finding update package...
I:Update location: SDCARD:/rom.zip
Opening update package...
I:Update file path: /sdcard/rom.zip
E:Can't open /sdcard/rom.zip
(bad)
Installation aborted.
Failure at line 3:
install_zip SDCARD:/rom.zip