# DragonFly Release 2.4

## Possible Upgrade Issues

* The kernel is unable to find the root and stops at the mountroot prompt.
  Due to the upgrade the drive may have changed names.
 * Hit scroll-lock on the console, scroll up and locate the root drive.
 * For BOOT+HAMMER try specifying: "hammer:xxxs1d", where xxx is the drive.
 * For UFS try specifying: "ufs:xxxs1a", where xxx is the drive.
 * Once you get the system up you may have to remount / read-write, then
   fix /etc/fstab and adjust /boot/loader.conf as necessary to specify
   the root mount using vfs.root.mountfrom="hammer:serno/SERIALNUMBER.s1d"
   (for example).
 * We recommend specifying mount points by serial number, using
   /dev/serno/SERIALNUMBER.s1PARTITION as necessary.  Also remember
   you may have a device specification in your /etc/rc.conf (for the dump device),
   and of course the root mount specification in /boot/loader.conf.

* Your kernel and world are out of sync.
 * tty's and pty's may not work properly in this case, you may have
   trouble getting a root prompt.
 * Try booting into single user mode and complete the installation.
 * Or boot the CD and re-upgrade.

* HAMMER-only installation fails with BTX errors or is unable to load
  the loader, or kernel.
 * An algorithmic bug in the loader's HAMMER implementation causes the
   loader to improperly parse file data in some cases.
 * All we can recommend here is to switch to a BOOT+HAMMER installation,
   which is fully supported and actually considerably easier to manage.
   An existing installation can be adjusted by stealing 256MB from your
   swap partition to create a UFS boot partition, naming it 'a'.  Then
   copy the HAMMER /boot into it (directly, not as a subdirectory called 'boot').
   Of course we'd prefer a completely clean install so the partitions are
   well ordered but stealing an 'a' partition from swap space will work
   if you can't afford to blow away the current drive.

* You have an AHCI SATA controller but the new AHCI driver is having
  problems detecting your drives.
 * There is a boot menu option to disable the AHCI driver, which will
   cause the kernel to fall back to the NATA driver.  Setting
   hint.ahci.disabled=1 in /boot/loader.conf will accomplish the same
   thing.

* The installer errors out while trying to install a disklabel.
 * Known issue.  We blew the partition cleaning dd.  Basically the
   installer wants to install a disklabel64 but there is a standard
   disklabel already installed.  For safety reasons the disklabel
   program refuses to blow away the old label.
 * You can blow away the whole disk or the slice from the emergency
   shell prompt (alt f3? alt f4?) and then start the installation over
   again.
 * dd if=/dev/zero of=/dev/RAWDISK bs=32k count=4 **This will blow
   away the whole disk**.  You can try it on just the slice, aka
   RAWDISKs1 but it is fairly dangerous to do so be careful.


## Known Issues

* Occasional panic after burning a CD.  This is a known issue
  which we hope to address in 2.4.1.
* Possible issues with kqueue operations getting stuck (w/ postfix).
  This issue is being investigated.
* 64-bit kernel is unable to probe USB mass storage devices.  This is a
  known issue which we hope to address in 2.4.1.