--- _ti_k3_r5_remoteproc.c	2025-12-17 13:39:01.235512803 -0800
+++ drivers/remoteproc/ti_k3_r5_remoteproc.c	2025-12-17 13:38:56.939514816 -0800
@@ -489,6 +489,7 @@
 	struct k3_r5_rproc *kproc = rproc->priv;
 	struct mbox_client *client = &kproc->client;
 	struct device *dev = kproc->dev;
+	int ret;
 
 	client->dev = dev;
 	client->tx_done = NULL;
@@ -501,6 +502,20 @@
 		return dev_err_probe(dev, PTR_ERR(kproc->mbox),
 				     "mbox_request_channel failed\n");
 
+	/*
+	 * Ping the remote processor, this is only for sanity-sake for now;
+	 * there is no functional effect whatsoever.
+	 *
+	 * Note that the reply will _not_ arrive immediately: this message
+	 * will wait in the mailbox fifo until the remote processor is booted.
+	 */
+	ret = mbox_send_message(kproc->mbox, (void *)RP_MBOX_ECHO_REQUEST);
+	if (ret < 0) {
+		dev_err(dev, "mbox_send_message failed: %d\n", ret);
+		mbox_free_channel(kproc->mbox);
+		return ret;
+	}
+
 	return 0;
 }
 
@@ -1518,10 +1533,6 @@
 			goto out;
 		}
 
-		ret = dma_coerce_mask_and_coherent(&rproc->dev, DMA_BIT_MASK(48));
-		if (ret)
-			dev_warn(dev, "Failed to set DMA mask (%d)\n", ret);
-
 		/* K3 R5s have a Region Address Translator (RAT) but no MMU */
 		rproc->has_iommu = false;
 		/* error recovery is not supported at present */