10-27-2019 11:57 AM
Systems engineer here. I have another solution that may help. I tried everything I could find online, including suggestions from the HP support group -- nothing worked.
Based on what I found, it appears the problem is simply an odd bug inside the firmware. Initially, I thought the problem was bad circuit board component -- some sort of hardware issue. But it seems (fingers crossed) to be a combination of the PCB design and the firmware are just buggy.
My printer had version 2011xyz of the firmware (you can see this in the 'Reports->Config' menu. The firmware version download on the website is 2014xyz. I figured that would be a good first step to resolve this boot bug, and the HP tech confirmed that upgrading should be the first step. But as we know, you can't actually run the firmware update utility when the printer is displaying that frustrating error (firmware corrupt, ready 2 download). When you attach the printer, the USB device is incorrectly identified as a different printer (3020 series), and the firmware update tool seems to fail thinking that no valid device is attached. Hp support will tell you to remove the device, manually add, get the PCL6 universal drivers, hold down buttons to reset, etc. None of that worked, for me anyway.
I left the printer in my garage for a month, then brought it inside and plugged it in. Incredibly, it fired right up, booted with no errors. I ran diag print reports, etc, worked great. Confirmed firmware was 2011. So, I next plugged the printer usb in to my Win8.1 laptop. USB correctly found the 1525 printer, installed drivers, I ran a test page, everything was great. I then proceeded with the firmware update. It completed (happy face at the end), but didn't seem to do anything. I ran a config test printer, and it still showed 2011. And oddly, the printer queue had large jobs that appears to be stuck. I figured, maybe I just need to power cycle the printer to load the newly installed firmware. So I did power cycle, and upon restart the printer was again dead -- "firmware corrupt". So, I unplugged, replugged, tried every button combination I could think of (looks like there is a way to load firmware from the DIMM too), nothing worked, and stopped just short of getting the baseball bat and going OfficeSpace on the thing.
Left the printer on my kitchen table for 3 days, unplugged. Powered up this morning before getting ready to take it to the trash, and again, it booted right up, no problem. unbelievable.
So, ran another diag page, found the firmware was still 2011 -- the last firimware flash failed, maybe because of those jammed printer jobs in the queue. Anyway, reconnected usb to win8.1 laptop, which again found the printer, ran a test page, worked perfectly. I then proceeded, again, to load the 2014 firmware utility. It found the printer, and proceeded to start.
And, the firmware update worked differently this time. About 50% through the update (based on the scrolling bar graph), the printer restarted itself. I panicked, since device restarts in the middle of firmware updates are often fatal. But, the printer continued to boot normally, displaying 'ready'. And, the update completed with another "smiley face". And, I ran another config test (this time, using the 'print config' button in the utility). The printer generated the config page, and confirmed it's now on firmware 2014.
I've since powered cycled it several times, tried everything I could to break it. And, seems to be working better. It now boots up every time, no more firmware errors. Could be a fluke, no clue. But, it would suggest that there was a bug in the firmware, and the circuit board has some sort of residual electricity that persists several days after being unplugged that the 2011 firmware can't process. I'd guess the 2014 firmware fixes the bug and works around the residual electricity issue and allows the unit to power on. Leaving the printer unplugged long enough allows that residual electricity to slowly discharge as expected. For me, it took about 3 days. I tried overnight, and it was still dead the next morning.
If you have a CP1525 printer displaying the 'firmware corrupt', try to unplug all the cables from the printer and it and leave it alone for a week. Then, plug it back in and see if it works. If so, try the 2014 firmware utility, and do not unplug or turn off the printer until the utility completes. I don't know why my first firmware upgrade attempt failed, but it does appear that if you can get the printer booted and the firmware loaded, that it does correct the firmware boot bug.