diff --git a/hw/soc_dma.c b/hw/soc_dma.c
index f46e260..4ff8cae 100644
--- a/hw/soc_dma.c
+++ b/hw/soc_dma.c
@@ -49,7 +49,7 @@
 static int fifo_size;
 void transfer_fifo2fifo(struct soc_dma_ch_s *ch)
 {
-    if (ch->bytes < fifo_size)
+    if (ch->bytes > fifo_size)
         fifo_buf = realloc(fifo_buf, fifo_size = ch->bytes);
 
     /* Implement as transfer_fifo2linear + transfer_linear2fifo.  */
@@ -251,6 +251,7 @@
     }
 
     soc_dma_reset(&s->soc);
+    fifo_size = 0;
 
     return &s->soc;
 }