Rebuilding World and Kernel on FreeBSD

Building the world and kernel on FreeBSD is just few steps procedure. The Handbook explains everything in great details. Here is short version.

1. Synchronize the OS source code (see here).
2. Configure make.conf.
3. Optional. Configure world options (file /etc/src.conf):

   WITHOUT_AMD=
   WITHOUT_ASSERT_DEBUG=
   # Need only few utilities from bind
   WITHOUT_BIND_DNSSEC=
   WITHOUT_BIND_ETC=
   WITHOUT_BIND_LIBS_LWRES=
   WITHOUT_BIND_MTREE=
   WITHOUT_BIND_NAMED=
   WITHOUT_BLUETOOTH=
   # This saves build time twice
   WITHOUT_CLANG=
   WITHOUT_FLOPPY=
   WITHOUT_FREEBSD_UPDATE=
   WITHOUT_GAMES=
   WITHOUT_GDB=
   WITHOUT_HTML=
   WITHOUT_INET6=
   WITHOUT_IPX=
   # On amd64, set to not build 32-bit library set
   #WITHOUT_LIB32=
   WITHOUT_LPR=
   WITHOUT_NCP=
   WITHOUT_NDIS=
   WITHOUT_PROFILE=
   WITHOUT_RCS=
   WITHOUT_SYSINSTALL=
   WITHOUT_TELNET=
   WITHOUT_WIRELESS=
   WITHOUT_WPA_SUPPLICANT_EAPOL=
   WITHOUT_ZFS=
   # If you are building world for jail
   WITHOUT_ACPI=
   WITHOUT_APM=
   WITHOUT_ATM=
   WITHOUT_AUTHPF=
   WITHOUT_BLUETOOTH=
   WITHOUT_BOOT=
   WITHOUT_CDDL=
   WITHOUT_DICT=
   WITHOUT_EXAMPLES=
   WITHOUT_FORTH=
   WITHOUT_GAMES=
   WITHOUT_GPIB=
   #WITHOUT_INFO=
   WITHOUT_IPFILTER=
   WITHOUT_IPFW=
   WITHOUT_IPX=
   WITHOUT_JAIL=
   WITHOUT_LEGACY_CONSOLE=
   #WITHOUT_MAN=
   #WITH_MAN_UTILS=
   WITHOUT_NETGRAPH=
   WITHOUT_NIS=
   WITHOUT_NTP=
   WITHOUT_PF=
   WITHOUT_PMC=
   WITHOUT_PPP=
   WITHOUT_PROFILE=
   WITHOUT_RESCUE=
   WITHOUT_ROUTED=
   WITHOUT_SHAREDOCS=
   WITHOUT_USB=
   

4. Configure Kernel:

   cd /usr/src/sys/i386/conf
   cp GENERIC /root/kernels/STABLE
   ln -s /root/kernels/STABLE
   

   Ensure the following (file /root/kernels/STABLE):

   #cpu            I486_CPU
   #cpu            I586_CPU
   cpu             I686_CPU
   ident           STABLE
   #makeoptions    DEBUG=-g
   

   Comment out other options that you find reasonable, e.g. INET6, etc. In order to narrow the device list to just one specific to your hardware try the following (where device_name is ahci, eisa, etc):

   dmesg | grep device_name 
   

   If the above does not return anything for your hardware go ahead and comment that device.
5. Build World and Kernel (this is time consuming and may take 50 and 15 mins accordingly):

   cd /usr/src/
   time make -sj4 buildworld
   time make -sj4 buildkernel KERNCONF=STABLE
   

6. Reboot to Single User Mode:

   shutdown now
   

7. Install Kernel and World:

   mount -u /
   mount -a -t ufs
   swapon -a
   cd /usr/src/
   make installkernel KERNCONF=STABLE
   make installworld
   

8. Update configuration files (automatically install any files that do not exist in the destination directory, attempt to auto upgrade files that have not been user modified):

   mergemaster -Ui
   

9. Clean up

   cd /usr/obj
   chflags -R noschg *
   rm -rf *
   

Reboot your system. You should have now system installed from source.