diff --git a/arch/Kconfig b/arch/Kconfig
index bbe99c17c2d..5cee40628b5 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -117,6 +117,12 @@ config ARCH_STACKDUMP
 	---help---
 		Enable to do stack dumps after assertions
 
+config ENDIAN_BIG
+	bool "Big Endian Architecture"
+	default n
+	---help---
+		Select if architecture operates using big-endian byte ordering.
+
 comment "Board Settings"
 
 config BOARD_LOOPSPERMSEC
diff --git a/arch/z80/Kconfig b/arch/z80/Kconfig
index a2764cb653d..12ab5dc0b28 100644
--- a/arch/z80/Kconfig
+++ b/arch/z80/Kconfig
@@ -13,56 +13,62 @@ config ARCH_CHIP_Z80
 	---help---
 		Classic ZiLOG z80 chip
 
-config ARCH_CHIP_Z8F640X
-	bool "Z8F640X"
-	select ARCH_CHIP_Z8
-	---help---
-		ZiLOG Z8F640X (z8 Encore)
-
 config ARCH_CHIP_Z8F6403
 	bool "Z8F6403"
 	select ARCH_CHIP_Z8
+	select ARCH_CHIP_Z8F640X
+	select ENDIAN_BIG
+	select HAVE_LOWUARTINIT
 	---help---
 		ZiLOG Z8F6403 (z8 Encore)
 
-config ARCH_CHIP_Z8F642X
-	bool "Z8F642X"
-	select ARCH_CHIP_Z8
-	---help---
-		ZiLOG Z8F642X (z8 Encore)
-
 config ARCH_CHIP_Z8F6423
 	bool "Z8F6423"
 	select ARCH_CHIP_Z8
+	select ARCH_CHIP_Z8F642X
+	select ENDIAN_BIG
+	select HAVE_LOWUARTINIT
 	---help---
 		ZiLOG Z8F6423 (z8 Encore)
 
 config ARCH_CHIP_EZ80F91
 	bool "EZ80F91"
 	select ARCH_CHIP_EZ80
+	select HAVE_LOWUARTINIT
 	---help---
 		ZiLOG EZ80F91 (ez80 Acclaim)
 
 config ARCH_CHIP_EZ80F92
 	bool "EZ80F92"
 	select ARCH_CHIP_EZ80
+	select HAVE_LOWUARTINIT
 	---help---
 		ZiLOG EZ80F92 (ez80 Acclaim)
 
 config ARCH_CHIP_EZ80F93
 	bool "EZ80F93"
 	select ARCH_CHIP_EZ80
+	select HAVE_LOWUARTINIT
 	---help---
 		ZiLOG EZ80F93 (ez80 Acclaim)
 
 endchoice
 
+config ARCH_CHIP_Z8F642X
+	bool
+
+config ARCH_CHIP_Z8F640X
+	bool
+
 config ARCH_CHIP_Z8
 	bool
 
 config ARCH_CHIP_EZ80
 	bool
 
+config HAVE_LOWUARTINIT
+	bool
+
 config ARCH_CHIP
 	string
 	default "z80"		if ARCH_CHIP_Z80
diff --git a/arch/z80/src/ez80/Kconfig b/arch/z80/src/ez80/Kconfig
index 6bde573f605..d257ca285ab 100644
--- a/arch/z80/src/ez80/Kconfig
+++ b/arch/z80/src/ez80/Kconfig
@@ -31,13 +31,6 @@ config EZ80_EMAC
 
 endmenu
 
-config HAVE_LOWUARTINIT
-	bool "Low UART Init"
-	default y if !EZ80_UART0 && !EZ80_UART1 && !EZ80_UART2
-	default n if EZ80_UART0 || EZ80_UART1 || EZ80_UART2
-	---help---
-		Provides low-level UART initialization logic as up_lowuartinit (only needed if there is no serial driver).
-
 if EZ80_EMAC
 
 config EZ80_FIAD
diff --git a/arch/z80/src/z8/Kconfig b/arch/z80/src/z8/Kconfig
index 1f0289f7ce4..2bf89905efa 100644
--- a/arch/z80/src/z8/Kconfig
+++ b/arch/z80/src/z8/Kconfig
@@ -4,4 +4,17 @@
 #
 
 if ARCH_CHIP_Z8
+
+# UART0/1 always enabled
+
+config Z8_UART0
+	bool
+	default y
+	select ARCH_HAVE_UART0
+
+config Z8_UART1
+	bool
+	default y
+	select ARCH_HAVE_UART1
+
 endif