iMac 20'' (Early 2009) Stuck on White Screen – Boot Selector Not Working

[T-Man_16]

Hello everyone,

I have a problem with my 20" iMac from early 2009. A few months ago, my father gave me the iMac to reinstall it and install a fresh operating system. At that time, the Mac had a 320GB Apple HDD and 8GB of RAM installed. Reinstalling proved difficult because the Mac does not show the boot selector. When I start with the Option key pressed, the screen just stays white, and the Mac does nothing. If I try to select a USB stick from the system via Startup Disk, it doesn't show up. However, in Disk Utility, my prepared USB stick is displayed as "bootable." In other forums, I had read that the HDD might be defective, so I replaced it with an SSD and reinstalled the OS (using a OSX 10.6 DVD and then updated to El Capitan). The problem persists.

To summarize:

• Mac does not show the boot selector; screen stays white
• El Capitan is currently installed
• My goal is to update to Monterey using OCLP

What I have already tried:

• Various USB sticks
• Different keyboards
• Tested the USB stick on another Mac; it appears in the boot selector
• NVRAM reset
• SMC reset
• Changed CMOS battery
• Ran "csrutil-disable" command in recovery
• Tried booting directly from the stick using the "bless" command
• Downloaded iMac EFI Version 1.4 and tried to reinstall it, thinking it might be faulty (installer wouldn't open because I already have the "latest" installed, Boot Rom Version IM91.008D.B08)

If you have any ideas or even a solution, I would appreciate a response. I'm slowly running out of ideas and patience.

Best regards,
T-Man_16

 

[Nguyen Duc Hieu]

Hello everyone,

I have a problem with my 20" iMac from early 2009. A few months ago, my father gave me the iMac to reinstall it and install a fresh operating system. At that time, the Mac had a 320GB Apple HDD and 8GB of RAM installed. Reinstalling proved difficult because the Mac does not show the boot selector. When I start with the Option key pressed, the screen just stays white, and the Mac does nothing. If I try to select a USB stick from the system via Startup Disk, it doesn't show up. However, in Disk Utility, my prepared USB stick is displayed as "bootable." In other forums, I had read that the HDD might be defective, so I replaced it with an SSD and reinstalled the OS (using a OSX 10.6 DVD and then updated to El Capitan). The problem persists.

To summarize:

• Mac does not show the boot selector; screen stays white
• El Capitan is currently installed
• My goal is to update to Monterey using OCLP

What I have already tried:

• Various USB sticks
• Different keyboards
• Tested the USB stick on another Mac; it appears in the boot selector
• NVRAM reset
• SMC reset
• Changed CMOS battery
• Ran "csrutil-disable" command in recovery
• Tried booting directly from the stick using the "bless" command
• Downloaded iMac EFI Version 1.4 and tried to reinstall it, thinking it might be faulty (installer wouldn't open because I already have the "latest" installed, Boot Rom Version IM91.008D.B08)

If you have any ideas or even a solution, I would appreciate a response. I'm slowly running out of ideas and patience.

Best regards,
T-Man_16

Try the below sequences, after do a tripple PRAM reset on your iMac 2009 (and still fail)
1. Remove the internal SSD, put it to a USB enclosure (A)
2. On another Mac, run OCLP in MANUAL mode, select the correct iMac 2009 20" model, then generate the EFI volume and overwrite to the (A) disk above.
3. Now put back the SSD removed from (A) to iMac 2009.
4. iMac 2009 is supposed to boot from the internal SSD with OCLP menu. You can still plug in the USB installer to install newer Mac OS...

 

[T-Man_16]

You are right. This will probably solve the problem going up to Monterey. But will this also solve the ground problem of the missing boot-selector? I initially wanted to solve this problem first before moving on, but if moving on to Monterey maybe is the solution, then I will try this method.

 

[Nguyen Duc Hieu]

You are right. This will probably solve the problem going up to Monterey. But will this also solve the ground problem of the missing boot-selector? I initially wanted to solve this problem first before moving on, but if moving on to Monterey maybe is the solution, then I will try this method.

No if the problem was caused by a firmware password....

 

[T-Man_16]

No if the problem was caused by a firmware password....

there is no firmware password on the Mac. I checked when I was in recovery

 

[T-Man_16]

I have news: so with holding the combination of option and "T" upon startup the iMac showed the boot picker with the internal SSD and a restart and shutdown button. On the right bottom corner was something like "REL xxxxxxxxxx" (x standing for numbers). But also there, no bootable usb drive. Has anyone any ideas?

 

[DeltaMac]

What macOS system, or Mac system installer, is on your "bootable" USB?
You say that your goal is to install Monterey (using OCLP).
What process did you use in the terminal to set up the Monterey installer on your USB stick?
(My question about that is with the Monterey installer, which has an unusual choice: there are 2 different createinstallmedia files, and one of those might not give you a bootable installer, even though it might appear to be correct. It's the one called createinstallmedia_yosemite. If you used THAT one, you might try remaking the installer drive, using the file without the _yosemite. This may not explain why your USB drive does not show as a bootable devic, but is worth testing, I think.
Is there ANYTHING else on that USB drive, such as other partitions?

Finally, if nothing else is helping with that USB installer, I would suggest using a different drive for your Monterey installer. I also occasionally have problems with the Boot-picker screen on older Intel Macs, but I just go to another installer that I keep (I probably have 10 different macOS installer drives, some with multiple bootable partitions, and a few with only one version on a drive. And, I sometimes struggle to boot anything on my own oldest iMac8,1 (Early 2008, 20-inch) I reinstall on that one every few months - it's a kind of test machine for some projects that I have. It is VERY finicky on reinstalls, as it refuses to restart automatically, and needs to be shut off, then booted from off before it will continue on with system updates (or any install that requires a reboot). Not a big issue, when I finally learned how to think one step ahead when it tried, but refused to reboot...

 

[T-Man_16]

I created the bootable usb with OCLP. Downloaded Monterey through OCLP and let the program build the usb stick. So I did not have to use terminal at all to build the stick.

Where can I look up if it's the "right" createinstallmedia?

On the usb drive is nothing else except the thing OCLP put on it. Also it does not have any other partitions.

I have already used 4 different drives, 2 of them being usb 2.0 and the other 2 being usb 3.0. The stick appears to be bootable and "correct" everytime...

What macOS system, or Mac system installer, is on your "bootable" USB?
You say that your goal is to install Monterey (using OCLP).
What process did you use in the terminal to set up the Monterey installer on your USB stick?
(My question about that is with the Monterey installer, which has an unusual choice: there are 2 different createinstallmedia files, and one of those might not give you a bootable installer, even though it might appear to be correct. It's the one called createinstallmedia_yosemite. If you used THAT one, you might try remaking the installer drive, using the file without the _yosemite. This may not explain why your USB drive does not show as a bootable devic, but is worth testing, I think.
Is there ANYTHING else on that USB drive, such as other partitions?

Finally, if nothing else is helping with that USB installer, I would suggest using a different drive for your Monterey installer. I also occasionally have problems with the Boot-picker screen on older Intel Macs, but I just go to another installer that I keep (I probably have 10 different macOS installer drives, some with multiple bootable partitions, and a few with only one version on a drive. And, I sometimes struggle to boot anything on my own oldest iMac8,1 (Early 2008, 20-inch) I reinstall on that one every few months - it's a kind of test machine for some projects that I have. It is VERY finicky on reinstalls, as it refuses to restart automatically, and needs to be shut off, then booted from off before it will continue on with system updates (or any install that requires a reboot). Not a big issue, when I finally learned how to think one step ahead when it tried, but refused to reboot...

 

[DeltaMac]

My usual tip when a USB bootable installer won't appear as a choice for booting, is to reset NVRAM, holding the keys for that, and waiting for the boot chime, then continue to hold the same 4 keys for 2 to 5 more chimes. (just a recommendation that I remember seeing 10 or 15 years ago. Someone referred to the 5 chimes as a full reset. I can't tell you why, or even if it is always effective, but simply an old tip that I continue to use. I do know (in my own experience) that an NVRAM reset often makes a boot drive that is slow to appear (slow to respond, etc) generally work better. Some Macs are simply slow to boot from external boot drives, whatever the source, particularly from USB thumb drives.
I make 20 or more bootable installers every month, of just about every Mac system version, from 10.5 Leopard to 15.1 Sequoia. The most reliable ones that I use are NVME/m.2 stick in a USB external enclosure for that. I always use the terminal to make installers, but I use that so often that I almost don't have to look as I type. The worst part about using the terminal, is that it's really easy to make a typing mistake.
I always test the bootable installers, particularly if I am making one for someone else. If it won't boot on the Mac that it was made for, then it doesn't work, usually because it was made incorrectly, or maybe a thumb drive that is nearing end of life. (I don't have a problem with trashing a thumb drive that I decide has been formatted/erased too many times)

 

[Nguyen Duc Hieu]

I recalled I didn't have any issue when installing Catalina on my iMac 24" early 2009.
The USB installer was created using dosdude1 patch.

 

[T-Man_16]

My usual tip when a USB bootable installer won't appear as a choice for booting, is to reset NVRAM, holding the keys for that, and waiting for the boot chime, then continue to hold the same 4 keys for 2 to 5 more chimes. (just a recommendation that I remember seeing 10 or 15 years ago. Someone referred to the 5 chimes as a full reset. I can't tell you why, or even if it is always effective, but simply an old tip that I continue to use. I do know (in my own experience) that an NVRAM reset often makes a boot drive that is slow to appear (slow to respond, etc) generally work better. Some Macs are simply slow to boot from external boot drives, whatever the source, particularly from USB thumb drives.
I make 20 or more bootable installers every month, of just about every Mac system version, from 10.5 Leopard to 15.1 Sequoia. The most reliable ones that I use are NVME/m.2 stick in a USB external enclosure for that. I always use the terminal to make installers, but I use that so often that I almost don't have to look as I type. The worst part about using the terminal, is that it's really easy to make a typing mistake.
I always test the bootable installers, particularly if I am making one for someone else. If it won't boot on the Mac that it was made for, then it doesn't work, usually because it was made incorrectly, or maybe a thumb drive that is nearing end of life. (I don't have a problem with trashing a thumb drive that I decide has been formatted/erased too many times)

Thanks for your reply! The NVRAM and PRAM reset have I done to this machine multiple times before. But this wasn't the solution for me.
The tip with external ssd drives is good, that I will be trying later. Thanks

 

[T-Man_16]

I recalled I didn't have any issue when installing Catalina on my iMac 24" early 2009.
The USB installer was created using dosdude1 patch.

Yess, the dosdude1 tool have I also used before and works pretty easy. The usb creation part of dosdude and oclp are pretty similar I would say. And for is not the problem, rather than the missing boot selector...

 

[T-Man_16]

Thanks for your reply! The NVRAM and PRAM reset have I done to this machine multiple times before. But this wasn't the solution for me.
The tip with external ssd drives is good, that I will be trying later. Thanks

I have tried setting up the external ssd. It appears to be formatted correctly and is bootable, but the iMac won't boot from it, neither the boot-selector appears. Everything is as it was...

 

[DeltaMac]

When you get the white screen on a reboot (and nothing else), does your iMac shut off immediately when you press and release the power button on the back?
If it simply shuts off, wait for a few seconds, press and release the power button, then try the Option-boot again. (leave your bootable USB attached to your iMac). Do you get the boot-picker screen using this method? If yes, that's exactly how my 2008 20-inch responds. (It does not show the boot-picker screen, only a grey screen. Shut off, then boot from power off brings it up (usually). Restart seldom works on that iMac for me. Maybe your 2009 works the same.

 

[T-Man_16]

When you get the white screen on a reboot (and nothing else), does your iMac shut off immediately when you press and release the power button on the back?
If it simply shuts off, wait for a few seconds, press and release the power button, then try the Option-boot again. (leave your bootable USB attached to your iMac). Do you get the boot-picker screen using this method? If yes, that's exactly how my 2008 20-inch responds. (It does not show the boot-picker screen, only a grey screen. Shut off, then boot from power off brings it up (usually). Restart seldom works on that iMac for me. Maybe your 2009 works the same.

Sometimes when I just power it on, the Mac stays on the white screen, sometimes it boots from the internal SSD. When I hold the option key while booting it stays on the white screen. When I then press the power button and release it, the Mac shuts down. Turning it back on the problem persists...

 

[DeltaMac]

I now think you have a firmware problem, somehow the firmware is corrupted. Replacing the logic board would fix that, making it not worth the money

 

[T-Man_16]

I now think you have a firmware problem, somehow the firmware is corrupted. Replacing the logic board would fix that, making it not worth the money

Thats also what I think now. Also tried to install the newest EFI Firmware for this Mac (1.4) directly from apple which didn't work and programs like rEFInd or rEFIt also didn't do the job...

 

[T-Man_16]

So far I haven't had any success. My guess also is that the firmware or efi is somehow corrupted and therefore the boot selector stays hidden. I won't work on the iMac anymore and just use it with El Capitan for now. Thanks for the help though.

 

[DeltaMac]

hmmm... ( Now that you don't have any pressure to boot from an EFI boot partition, or a newer bootable USB installer)-- Does the Option-boot picker screen show your El Capitan boot? I'm just curious...