- <td><tt>internal</tt>, <tt>external</tt>, <tt>optical</tt>, <tt>hdbios</tt>, <tt>biosexternal</tt>, <tt>cd</tt>, and <tt>manual</tt></td>
- <td>Tells rEFInd what methods to use to locate boot loaders. The <tt>internal</tt>, <tt>external</tt>, and <tt>optical</tt> parameters tell rEFInd to scan for EFI boot loaders on internal, external, and optical (CD, DVD, and Blu-ray) devices, respectively. The <tt>hdbios</tt>, <tt>biosexternal</tt>, and <tt>cd</tt> parameters are similar, but scan for BIOS boot loaders. (Note that the BIOS options scan more thoroughly and actively on Macs than on UEFI-based PCs; for the latter, only options in the firmware's boot list are scanned, as described on the <a href="using.html">Using rEFInd</a> page.) The <tt>manual</tt> parameter tells rEFInd to scan the configuration file for manual settings. You can specify multiple parameters to have the program scan for multiple boot loader types. When you do so, the order determines the order in which the boot loaders appear in the menu. The default is <tt>internal, external, optical, manual</tt> on most systems, but <tt>internal, hdbios, external, biosexternal, optical, cd, manual</tt> on Macs.</td>
+ <td><tt>internal</tt>, <tt>external</tt>, <tt>optical</tt>, <tt>netboot</tt>, <tt>hdbios</tt>, <tt>biosexternal</tt>, <tt>cd</tt>, and <tt>manual</tt></td>
+ <td>Tells rEFInd what methods to use to locate boot loaders. The <tt>internal</tt>, <tt>external</tt>, and <tt>optical</tt> parameters tell rEFInd to scan for EFI boot loaders on internal, external, and optical (CD, DVD, and Blu-ray) devices, respectively. The <tt>netboot</tt> option relies on the presence of the <tt>ipxe.efi</tt> and <tt>ipxe_discover.efi</tt> program files in the <tt>EFI/tools</tt> directory to assist with network (Preboot Execution Environment, or PXE) booting. Note that <tt>netboot</tt> is experimental. See the <tt>BUILDING.txt</tt> file for information on building the necessary binaries. The <tt>hdbios</tt>, <tt>biosexternal</tt>, and <tt>cd</tt> parameters are similar, but scan for BIOS boot loaders. (Note that the BIOS options scan more thoroughly and actively on Macs than on UEFI-based PCs; for the latter, only options in the firmware's boot list are scanned, as described on the <a href="using.html">Using rEFInd</a> page.) The <tt>manual</tt> parameter tells rEFInd to scan the configuration file for manual settings. You can specify multiple parameters to have the program scan for multiple boot loader types. When you do so, the order determines the order in which the boot loaders appear in the menu. The default is <tt>internal, external, optical, manual</tt> on most systems, but <tt>internal, hdbios, external, biosexternal, optical, cd, manual</tt> on Macs.</td>
+</tr>
+<tr>
+ <td><tt>uefi_deep_legacy_scan</tt></td>
+ <td>none or one of <tt>true</tt>, <tt>on</tt>, <tt>1</tt>, <tt>false</tt>, <tt>off</tt>, or <tt>0</tt></td>
+ <td>Tells rEFInd how aggressively to scan for BIOS/CSM/legacy boot loaders on UEFI-based PCs. Ordinarily or if this option is set to <tt>false</tt>, <tt>off</tt>, or <tt>0</tt>, rEFInd presents only those options that were available in the NVRAM when it launched. When uncommented with no option or with <tt>true</tt>, <tt>on</tt>, or <tt>1</tt> set, rEFInd adds every possible BIOS-mode boot device (of types specified by <tt>scanfor</tt>) as a BIOS/CSM/legacy boot option. This latter behavior is sometimes required to detect USB flash drives or hard disks beyond the first one.</td>