diff --git a/sys/arm64/arm64/machdep.c b/sys/arm64/arm64/machdep.c
--- a/sys/arm64/arm64/machdep.c
+++ b/sys/arm64/arm64/machdep.c
@@ -754,7 +754,7 @@
 		return;
 	}
 
-	if (OF_install(OFW_FDT, 0) == FALSE)
+	if (!OF_install(OFW_FDT, 0))
 		panic("Cannot install FDT");
 
 	if (OF_init((void *)dtbp) != 0)
diff --git a/sys/dev/ofw/ofw_bus_subr.c b/sys/dev/ofw/ofw_bus_subr.c
--- a/sys/dev/ofw/ofw_bus_subr.c
+++ b/sys/dev/ofw/ofw_bus_subr.c
@@ -641,7 +641,7 @@
 	phandle_t iparent;
 	uint32_t icells, *intr;
 	int err, i, irqnum, nintr, rid;
-	boolean_t extended;
+	bool extended;
 
 	nintr = OF_getencprop_alloc_multi(node, "interrupts",  sizeof(*intr),
 	    (void **)&intr);
@@ -707,7 +707,7 @@
 	phandle_t iparent;
 	uint32_t icells, *intr;
 	int err, i, nintr, rid;
-	boolean_t extended;
+	bool extended;
 
 	nintr = OF_getencprop_alloc_multi(node, "interrupts",  sizeof(*intr),
 	    (void **)&intr);
diff --git a/sys/dev/ofw/ofw_cpu.h b/sys/dev/ofw/ofw_cpu.h
--- a/sys/dev/ofw/ofw_cpu.h
+++ b/sys/dev/ofw/ofw_cpu.h
@@ -30,6 +30,6 @@
 #define _DEV_OFW_OFW_CPU_H_
 
 typedef bool (*ofw_cpu_foreach_cb)(u_int, phandle_t, u_int, pcell_t *);
-int ofw_cpu_early_foreach(ofw_cpu_foreach_cb, boolean_t);
+int ofw_cpu_early_foreach(ofw_cpu_foreach_cb, bool);
 
 #endif /* _DEV_OFW_OFW_CPU_H_ */
diff --git a/sys/dev/ofw/ofw_cpu.c b/sys/dev/ofw/ofw_cpu.c
--- a/sys/dev/ofw/ofw_cpu.c
+++ b/sys/dev/ofw/ofw_cpu.c
@@ -151,7 +151,7 @@
 struct ofw_cpu_softc {
 	struct pcpu	*sc_cpu_pcpu;
 	uint32_t	 sc_nominal_mhz;
-	boolean_t	 sc_reg_valid;
+	bool		 sc_reg_valid;
 	pcell_t		 sc_reg[2];
 };
 
@@ -335,7 +335,7 @@
 }
 
 int
-ofw_cpu_early_foreach(ofw_cpu_foreach_cb callback, boolean_t only_runnable)
+ofw_cpu_early_foreach(ofw_cpu_foreach_cb callback, bool only_runnable)
 {
 	phandle_t node, child;
 	pcell_t addr_cells, reg[2];
diff --git a/sys/dev/ofw/openfirm.h b/sys/dev/ofw/openfirm.h
--- a/sys/dev/ofw/openfirm.h
+++ b/sys/dev/ofw/openfirm.h
@@ -83,8 +83,8 @@
  * interface as the Open Firmware access mechanism, OF_init initializes it.
  */
 
-boolean_t	OF_install(char *name, int prio);
-int		OF_init(void *cookie);
+bool	OF_install(char *name, int prio);
+int	OF_init(void *cookie);
 
 /*
  * Known Open Firmware interface names
diff --git a/sys/dev/ofw/openfirm.c b/sys/dev/ofw/openfirm.c
--- a/sys/dev/ofw/openfirm.c
+++ b/sys/dev/ofw/openfirm.c
@@ -96,7 +96,7 @@
 
 static SLIST_HEAD(, xrefinfo) xreflist = SLIST_HEAD_INITIALIZER(xreflist);
 static struct mtx xreflist_lock;
-static boolean_t xref_init_done;
+static bool xref_init_done;
 
 #define	FIND_BY_XREF	0
 #define	FIND_BY_NODE	1
@@ -193,7 +193,7 @@
  */
 SET_DECLARE(ofw_set, ofw_def_t);
 
-boolean_t
+bool
 OF_install(char *name, int prio)
 {
 	ofw_def_t *ofwp, **ofwpp;
@@ -202,7 +202,7 @@
 	/* Allow OF layer to be uninstalled */
 	if (name == NULL) {
 		ofw_def_impl = NULL;
-		return (FALSE);
+		return (false);
 	}
 
 	/*
@@ -216,11 +216,11 @@
 		    prio >= curr_prio) {
 			curr_prio = prio;
 			ofw_def_impl = ofwp;
-			return (TRUE);
+			return (true);
 		}
 	}
 
-	return (FALSE);
+	return (false);
 }
 
 /* Initializer */
diff --git a/sys/powerpc/include/ofw_machdep.h b/sys/powerpc/include/ofw_machdep.h
--- a/sys/powerpc/include/ofw_machdep.h
+++ b/sys/powerpc/include/ofw_machdep.h
@@ -42,7 +42,7 @@
 void OF_getetheraddr(device_t dev, u_char *addr);
 
 void OF_initial_setup(void *fdt_ptr, void *junk, int (*openfirm)(void *));
-boolean_t OF_bootstrap(void);
+bool OF_bootstrap(void);
 
 void OF_reboot(void);
 
diff --git a/sys/powerpc/ofw/ofw_machdep.c b/sys/powerpc/ofw/ofw_machdep.c
--- a/sys/powerpc/ofw/ofw_machdep.c
+++ b/sys/powerpc/ofw/ofw_machdep.c
@@ -595,10 +595,10 @@
 	fdt = fdt_ptr;
 }
 
-boolean_t
+bool
 OF_bootstrap(void)
 {
-	boolean_t status = FALSE;
+	bool status = false;
 	int err = 0;
 
 #ifdef AIM
@@ -613,8 +613,8 @@
 			#endif
 		}
 
-		if (status != TRUE)
-			return status;
+		if (!status)
+			return (status);
 
 		err = OF_init(openfirmware);
 	} else
@@ -629,8 +629,8 @@
 #endif
 
 		status = OF_install(OFW_FDT, 0);
-		if (status != TRUE)
-			return status;
+		if (!status)
+			return (status);
 
 #ifdef AIM /* AIM-only for now -- Book-E does this remapping in early init */
 		/* Get the FDT size for mapping if we can */
@@ -668,15 +668,15 @@
 	 */
 	else {
 		status = OF_install(OFW_FDT, 0);
-		if (status != TRUE)
-			return status;
+		if (!status)
+			return (status);
 		err = OF_init(&fdt_static_dtb);
 	}
 	#endif
 
 	if (err != 0) {
 		OF_install(NULL, 0);
-		status = FALSE;
+		status = false;
 	}
 
 	return (status);
diff --git a/sys/riscv/riscv/machdep.c b/sys/riscv/riscv/machdep.c
--- a/sys/riscv/riscv/machdep.c
+++ b/sys/riscv/riscv/machdep.c
@@ -321,7 +321,7 @@
 		return;
 	}
 
-	if (OF_install(OFW_FDT, 0) == FALSE)
+	if (!OF_install(OFW_FDT, 0))
 		panic("Cannot install FDT");
 
 	if (OF_init((void *)dtbp) != 0)
diff --git a/sys/x86/x86/fdt_machdep.c b/sys/x86/x86/fdt_machdep.c
--- a/sys/x86/x86/fdt_machdep.c
+++ b/sys/x86/x86/fdt_machdep.c
@@ -46,7 +46,7 @@
 	void *dtbp, *mdp;
 	int error;
 
-	if (OF_install(OFW_FDT, 0) == FALSE) {
+	if (!OF_install(OFW_FDT, 0)) {
 		error = ENXIO;
 		goto out;
 	}