diff --git a/EmulatorPkg/EmulatorPkg.dsc b/EmulatorPkg/EmulatorPkg.dsc
index e0c6161..dfcd476 100644
--- a/EmulatorPkg/EmulatorPkg.dsc
+++ b/EmulatorPkg/EmulatorPkg.dsc
@@ -228,7 +228,7 @@
gEmulatorPkgTokenSpaceGuid.PcdEmuCpuModel|L"Intel(R) Processor Model"
gEmulatorPkgTokenSpaceGuid.PcdEmuCpuSpeed|L"3000"
- # 0-PCANSI, 1-VT100, 2-VT00+, 3-UTF8
+ # 0-PCANSI, 1-VT100, 2-VT00+, 3-UTF8, 4-TTYTERM
gEfiMdePkgTokenSpaceGuid.PcdDefaultTerminalType|1
[PcdsDynamicDefault.common.DEFAULT]
diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
index bda6550..598a6d0 100644
--- a/MdePkg/MdePkg.dec
+++ b/MdePkg/MdePkg.dec
@@ -2012,8 +2012,9 @@
# 1 - VT100
# 2 - VT100+
# 3 - UTF8
+ # 4 - TTYTERM, NOT defined in UEFI SPEC
# @Prompt Default Terminal Type.
- # @ValidRange 0x80000001 | 0 - 3
+ # @ValidRange 0x80000001 | 0 - 4
gEfiMdePkgTokenSpaceGuid.PcdDefaultTerminalType|0|UINT8|0x00000024
## Error level for hardware recorder.