create new boot image and system won't reboot

I did did a re-build of a boot image, but didn’t change anything in the build file, and when I put the new boot image in place the system won’t re-boot.

When it comes up I get the message …C, and then it stops.

If I put the original .boot file back in place and then reboot the system comes right up.

I did the exact same process on 2 other nodes and they came right up.

Has anyone heard of this or have any suggestions on what I can do.

The system is running version 4.25 of QNX

Maybe your new boot image file comes on your HDD “higher” then boundary 1024th cylinder. What is the size of your HDD? Is the QNX4 partition exceeding 1024th cylinder (if first partition then larger than approx. 8GB)?

Your new bootimage will be placed on the same place as the old one is only if the new one is smaller or equal in size. If your new bootimage is larger than the old one there is a possibility that it is placed above 1024th cylinder. But this is only possible if youre filesystem has approx 8G in use. If your filesystem is beyond 8G your BIOS assumes the harddrive differnet as the QNX4 Fsys.eide do.

From the docs:

[i]You can boot only from OS images that are loaded from within the first 1024 cylinders of the disk. This means that while you may be able to initially install and boot from a partition which extends past the 1024th cylinder, it will someday fail when you go to update the boot image because the location of some of its blocks may change. When this happens you will have a system which is no longer bootable.

Avoid this problem by creating a separate partition to boot from that lies entirely within the first 1024 cylinders of the hard drive, and use a second partition to access the additional space on the drive. (The boot partition may be quite small – just a few megabytes will suffice.)[/i]

This came to me some time ago… Maybe you will want to reinstall a new hard disk with the new boot image, following the mentioned recommendations and transfer old data to the new disk…


  1. We usually create a first small boot partition for system’s files (let’s say 8 GB), and others partitions for large data storage (databases, etc)

  2. If those partitions will have more than 40 GB you MUST have updated Fsys, and Fsys.eide to the latest version (this is update your whole system) and when you build your boot image, it’s very important that you add “-Hdisk<disk_capacity_in_GB>” to Fsys in order to set the a bigger heap-size than the default (which was enough some years ago, but no nowadays…)

For example: Fsys … -Hdisk120

You can read more in: … #Heap_size

I hope you’ll find this useful.