diff --git a/firmware/pcm.c b/firmware/pcm.c
index 766ec0491d..19c76a8a10 100644
--- a/firmware/pcm.c
+++ b/firmware/pcm.c
@@ -202,7 +202,7 @@ void pcm_do_peak_calculation(struct pcm_peaks *peaks, bool active,
     if (active)
     {
         struct pcm_sink* sink = sinks[cur_sink];
-        if (sink->configured_freq == -1UL)
+        if (sink->configured_freq == -1U)
         {
             logf("not configured yet");
             return;
@@ -250,7 +250,7 @@ void pcm_init(void)
     for(size_t i = 0; i < ARRAYLEN(sinks); i += 1) {
         struct pcm_sink* sink = sinks[i];
         sink->pending_freq = sink->caps.default_freq;
-        sink->configured_freq = -1UL;
+        sink->configured_freq = -1U;
         sink->pcm_is_ready = false;
         sink->ops.init();
     }
diff --git a/firmware/pcm_mixer.c b/firmware/pcm_mixer.c
index 92da971fb1..a0d26fc86d 100644
--- a/firmware/pcm_mixer.c
+++ b/firmware/pcm_mixer.c
@@ -33,7 +33,7 @@
    before the last samples are sent to the codec and so things are done in
    parallel (as much as possible) with sending-out data. */
 
-static unsigned int mixer_sampr = -1UL;
+static unsigned int mixer_sampr = -1U;
 static unsigned int mix_frame_size = MIX_FRAME_SAMPLES*4;
 
 /* Define this to nonzero to add a marker pulse at each frame start */
@@ -266,7 +266,7 @@ static void mixer_start_pcm(void)
 #endif
 
     /* Requires a shared global sample rate for all channels */
-    if (mixer_sampr == -1UL)
+    if (mixer_sampr == -1U)
         mixer_sampr = pcm_get_frequency();
     else
         pcm_set_frequency(mixer_sampr);