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Find missing FireWire devices System
After an app (VirtuFrame) crashed my Mac Mini, I discovered upon rebooting that my LaCie external FireWire drive was no longer visible. I disconnected and reconnected the cable several times, to no avail. It wasn't visible in either the Disk Utility or the System Profiler. I then reformatted the drive, but still no luck (good thing I didn't have any irreplaceable data on there). But when I connected it via USB cable, it showed up immediately. Apparently, the crash had somehow hammered my Firewire IO subsystem. After connecting via USB, I tried updating the FireWire firmware on the drive, but it still wasn't visible.

Based on advice I gleaned from a number of forums, I then tried the following: I shut down the Mini, unplugged it, and let it sit for five minutes -- this flushes the volatile RAM. When I rebooted, the drive was visible! Another suggestion is to wipe the PRAM: reboot and hold down Option-Command-P-R while booting (before you see the grey screen) and until the login screen comes up. After logging in, the drive should be visible.

If you're still stuck, search the Apple site or other locations for "Firewire bug."
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Find missing FireWire devices
Authored by: eabando on Aug 30, '05 11:31:38AM

I've also had issues with sporadic firewire drives not appearing. Powering up the drives well in advance of the mac also seems to help, sometimes.

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Find missing FireWire devices
Authored by: snyvlboi on Aug 30, '05 02:58:00PM

Holding Cmd+Opt+P+R will not perform as noted in this hint. When held, that particular key combination will continually reboot your Mac until you release it.

The rule of thumb is to hold the keys down until you hear the startup chime three times (I don't know where that originated; I've read multiple, conflicting reasons for doing this. None of them hold water.).

After the third chime, release the keys.



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Clearing P-RAM and resetting the PMU are different
Authored by: danieleran on Aug 30, '05 04:52:12PM

Macs' 'Parameter-RAM' and 'NonVolatle-RAM' are like a preferences files in firmware. Clearing the P-RAM is useful only when there is something corrupt written to this battery backed RAM. Holding down Apple+Option+P+R on boot will reset the P-RAM, and sometimes fix strange behavior such as failure to find the startup volume. P-RAM was used more extensively under Classic OS 9, and therefore was a primary troubleshooting step.

The Power Management Unit, or PMU, is the self contained computer on Macs that (among another things) allows you to schedule it to turn itself on or off. If this gets messed up, you can similarly reset it. On PowerMacs prior to the G5, you had to open your Mac up and carefully touch the PMU reset button on the logic board. If you touched it twice, or for too long, you risked crashing the PMU computer and draining your battery, which would then cause P-RAM to fail to hold values (including the time and date for the clock).

On newer Macs, including the latest G5s and apparently the Mac mini, you can reset the SMU (System Management Unit, which replaces the former PMU) by simply unplugging the unit and letting it sit unpowered for a 15 seconds.

PMU:
http://docs.info.apple.com/article.html?artnum=2238

SMU:
http://docs.info.apple.com/article.html?artnum=300341



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Clearing P-RAM and resetting the PMU are different
Authored by: macshome on Aug 31, '05 03:40:11PM

Just to fill in some fun backstory from WWDC this year...

It's not cmd-opt-p-r. It's cmd-opt-r-p. The original designers were thinking "reset pram" not "pram".

I've always gone with the cmd-opt-p-r though, as I could tell users to remember the word "copper".

Josh

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http://www.afp548.com
Breaking my server to save yours.



[ Reply to This | # ]
Clearing P-RAM and resetting the PMU are different
Authored by: macshome on Aug 31, '05 03:40:12PM

Just to fill in some fun backstory from WWDC this year...

It's not cmd-opt-p-r. It's cmd-opt-r-p. The original designers were thinking "reset pram" not "pram".

I've always gone with the cmd-opt-p-r though, as I could tell users to remember the word "copper".

Josh

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http://www.afp548.com
Breaking my server to save yours.



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Why the reboot loop
Authored by: jms1 on Aug 31, '05 01:15:31PM

When the machine starts up, the boot code (in the OpenFirmware) looks at the keyboard and looks for certain combinations. If it sees Cmd, Opt, P, and R all pressed, it jumps to a routine which (1) resets the PRAM, (2) plays the three tones, and (3) resets the machine.

After the reset, the same boot code scans the keyboard again. If the same keys are still down, guess what- the same three-step routine runs again.

Which means that if you don't release the keys, YOU cause a loop- and since one of the steps is a total reset of the machine, there is no way for the machine to detect it as a loop.

I don't see anything confusing about this, or what "doesn't hold water" about it.



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Find missing FireWire devices
Authored by: Jonathan David on Aug 30, '05 04:38:42PM

This happened to me with my LaCie 320 Gb external drive - if I try to connect it to the firewire port it just cuts out.

However I got a cable to go from 400 to 800 and plugged it into one of the two 800 ports and it came up just fine - still at the 400 speed but that is plenty fast.

I thought I had damaged the firewire port but I have no way to check this.

Jonathan



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Find missing FireWire devices
Authored by: gidds on Aug 30, '05 04:54:51PM
I've seen slightly different advice. Apparently, the Firewire circuitry can get into a tizz; the solution is to turn the machine off, unplug all Firewire cables, leave for five minutes, then plug everything back in and turn on.

No idea if that's the real reason or the best solution, but it's worked for me when my G4 decided to ignore my iPod and nothing else worked.

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Andy/

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Find missing FireWire devices
Authored by: tehon3299 on Aug 30, '05 05:14:26PM

I have also seen this problem with my 40gig iPod. I can plug the iPod in once and it will mount fine. If I eject it and plug it in again, it will not mount until I reset it by holding Menu+Center buttons. This is on my 15" PowerBook. How would you recommend trying to fix it?? Pull the battery and unplug the power and firewire cable for 5 minutes and try again??



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I think you're right
Authored by: lullabud on Aug 31, '05 03:06:35PM

I've had numerous firewire related problems when connecting several devices on a hub. (Camcorder, ipod, 2 external drives, and powerbook.) I have definitely found that if they lock up, when you unplug them all for a few minutes then plug them back in it will very likely work again.



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Find missing FireWire devices
Authored by: natol on Aug 31, '05 01:03:11PM

If you are up to it you can use open firmware to fix the firewire issue.

Caution : If the openfirmware is messed up it could cause your machine not to be bootable any longer.
Please proceed with caution.

Start the Mac after you hear the boot tone hold down
The apple (command) option o f keys.
It should boot up to a grey screen with what looks like a command prompt.
It will say something like type in mac-boot yadda yadda
Then
>

Type this in exactly while hitting enter after every line

reset-nvram
set-defaults
reset-all

after the last command it will reboot the Mac and the firewire should be visible again.

This also fixes some battery issues with PowerBooks such as if they are loosing their charge.



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Coincidentally...
Authored by: lullabud on Aug 31, '05 03:03:45PM

I was trying to recover information from a crashed hard drive by booting up my Powerbook in target disk mode. It wouldn't show up on my G5. After resetting the pram by doing the old cmd-opt-p-r trick, it worked fine. Never thought pram corruption would keep target disk mode from working...



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