diff --git a/kernel/unified/Kconfig b/kernel/unified/Kconfig
index 22d8b050a11..d1c5b342c00 100644
--- a/kernel/unified/Kconfig
+++ b/kernel/unified/Kconfig
@@ -45,8 +45,16 @@ config NUM_COOP_PRIORITIES
 	This can be set to zero to disable cooperative scheduling. Cooperative
 	threads always preempt preemptible threads.
 
-	Each priority requires an extra 8 bytes of RAM. If there are more than
-	32 total priorities, an extra 4 bytes is required.
+	Each priority requires an extra 8 bytes of RAM. Each set of 32 extra
+	total priorities require an extra 4 bytes and add one possible
+	iteration to loops that search for the next thread to run.
+
+	The total number of priorities is
+
+	   NUM_COOP_PRIORITIES + NUM_PREEMPT_PRIORITIES + 1
+
+	The extra one is for the idle thread, which must run at the lowest
+	priority, and be the only thread at that priority.
 
 config NUM_PREEMPT_PRIORITIES
 	int
@@ -58,11 +66,16 @@ config NUM_PREEMPT_PRIORITIES
 
 	This can be set to 0 to disable preemptible scheduling.
 
-	The idle thread is always installed as a preemptible thread of the
-	lowest priority.
+	Each priority requires an extra 8 bytes of RAM. Each set of 32 extra
+	total priorities require an extra 4 bytes and add one possible
+	iteration to loops that search for the next thread to run.
 
-	Each priority requires an extra 8 bytes of RAM. If there are more than
-	32 total priorities, an extra 4 bytes is required.
+	The total number of priorities is
+
+	   NUM_COOP_PRIORITIES + NUM_PREEMPT_PRIORITIES + 1
+
+	The extra one is for the idle thread, which must run at the lowest
+	priority, and be the only thread at that priority.
 
 config PRIORITY_CEILING
 	int
diff --git a/kernel/unified/include/kernel_structs.h b/kernel/unified/include/kernel_structs.h
index d9db1d75a30..03a5dc6c480 100644
--- a/kernel/unified/include/kernel_structs.h
+++ b/kernel/unified/include/kernel_structs.h
@@ -107,7 +107,7 @@ struct _ready_q {
 	struct k_thread *cache;
 
 	/* bitmap of priorities that contain at least one ready thread */
-	uint32_t prio_bmap[1];
+	uint32_t prio_bmap[K_NUM_PRIO_BITMAPS];
 
 	/* ready queues, one per priority */
 	sys_dlist_t q[K_NUM_PRIORITIES];
diff --git a/kernel/unified/include/ksched.h b/kernel/unified/include/ksched.h
index 2fc71c0c182..8c091eba7cd 100644
--- a/kernel/unified/include/ksched.h
+++ b/kernel/unified/include/ksched.h
@@ -167,17 +167,32 @@ static inline int _get_ready_q_q_index(int prio)
 	return prio + CONFIG_NUM_COOP_PRIORITIES;
 }
 
-#if (K_NUM_PRIORITIES > 32)
-	#error not supported yet
-#endif
-
 /* find out the currently highest priority where a thread is ready to run */
 /* interrupts must be locked */
 static inline int _get_highest_ready_prio(void)
 {
-	uint32_t ready = _ready_q.prio_bmap[0];
+	int bitmap = 0;
+	uint32_t ready_range;
 
-	return find_lsb_set(ready) - 1 - CONFIG_NUM_COOP_PRIORITIES;
+#if (K_NUM_PRIORITIES <= 32)
+	ready_range = _ready_q.prio_bmap[0];
+#else
+	for (;; bitmap++) {
+
+		__ASSERT(bitmap < K_NUM_PRIO_BITMAPS, "prio out-of-range\n");
+
+		if (_ready_q.prio_bmap[bitmap]) {
+			ready_range = _ready_q.prio_bmap[bitmap];
+			break;
+		}
+	}
+#endif
+
+	int abs_prio = (find_lsb_set(ready_range) - 1) + (bitmap << 5);
+
+	__ASSERT(abs_prio < K_NUM_PRIORITIES, "prio out-of-range\n");
+
+	return abs_prio - CONFIG_NUM_COOP_PRIORITIES;
 }
 
 /*
diff --git a/kernel/unified/include/nano_internal.h b/kernel/unified/include/nano_internal.h
index f122b3fb9cb..46ae901814b 100644
--- a/kernel/unified/include/nano_internal.h
+++ b/kernel/unified/include/nano_internal.h
@@ -28,6 +28,8 @@
 #define K_NUM_PRIORITIES \
 	(CONFIG_NUM_COOP_PRIORITIES + CONFIG_NUM_PREEMPT_PRIORITIES + 1)
 
+#define K_NUM_PRIO_BITMAPS ((K_NUM_PRIORITIES + 31) >> 5)
+
 #ifndef _ASMLANGUAGE
 
 #ifdef __cplusplus
diff --git a/kernel/unified/sched.c b/kernel/unified/sched.c
index 361ac4f951f..74090cb78c2 100644
--- a/kernel/unified/sched.c
+++ b/kernel/unified/sched.c
@@ -348,7 +348,11 @@ k_tid_t k_current_get(void)
 /* debug aid */
 void _dump_ready_q(void)
 {
-	K_DEBUG("bitmap: %x\n", _ready_q.prio_bmap[0]);
+	K_DEBUG("bitmaps: ");
+	for (int bitmap = 0; bitmap < K_NUM_PRIO_BITMAPS; bitmap++) {
+		K_DEBUG("%x", _ready_q.prio_bmap[bitmap]);
+	}
+	K_DEBUG("\n");
 	for (int prio = 0; prio < K_NUM_PRIORITIES; prio++) {
 		K_DEBUG("prio: %d, head: %p\n",
 			prio - CONFIG_NUM_COOP_PRIORITIES,