diff --git a/src/cart/README.env b/src/cart/README.env
index 6457ea19467..6bad14ad41e 100644
--- a/src/cart/README.env
+++ b/src/cart/README.env
@@ -211,3 +211,5 @@ This file lists the environment variables used in CaRT.
    traffic congestion. Available options are: "unspec" (default), "best_effort",
    "low_latency", "bulk_data".
 
+ . CRT_CXI_INIT_RETRY
+   Retry count for HG_Init_opt2() when initializing the CXI provider (default = 3).
diff --git a/src/cart/crt_hg.c b/src/cart/crt_hg.c
index 8f2395a44ff..f1dd6a3f2c3 100644
--- a/src/cart/crt_hg.c
+++ b/src/cart/crt_hg.c
@@ -1,5 +1,6 @@
 /*
  * (C) Copyright 2016-2024 Intel Corporation.
+ * (C) Copyright 2025 Hewlett Packard Enterprise Development LP
  *
  * SPDX-License-Identifier: BSD-2-Clause-Patent
  */
@@ -834,6 +835,7 @@ crt_hg_class_init(crt_provider_t provider, int ctx_idx, bool primary, int iface_
 	char			addr_str[CRT_ADDR_STR_MAX_LEN] = {'\0'};
 	size_t			str_size = CRT_ADDR_STR_MAX_LEN;
 	struct crt_prov_gdata	*prov_data;
+	uint32_t                 retry_count = 0;
 	int			rc = DER_SUCCESS;
 
 	prov_data = crt_get_prov_gdata(primary, provider);
@@ -869,9 +871,17 @@ crt_hg_class_init(crt_provider_t provider, int ctx_idx, bool primary, int iface_
 		init_info.traffic_class = (enum na_traffic_class)crt_gdata.cg_swim_tc;
 	if (thread_mode_single)
 		init_info.na_init_info.thread_mode = NA_THREAD_MODE_SINGLE;
-
+retry:
 	hg_class = HG_Init_opt2(info_string, crt_is_service(), HG_VERSION(2, 4), &init_info);
 	if (hg_class == NULL) {
+		/** workaround for DAOS-16990, DAOS-17011 - retry a few times on init */
+		if (provider == CRT_PROV_OFI_CXI && !crt_is_service() &&
+		    retry_count < crt_gdata.cg_hg_init_retry_cnt) {
+			retry_count++;
+			D_WARN("Could not initialize HG class; retrying (%d)\n", retry_count);
+			sleep(retry_count * 5);
+			goto retry;
+		}
 		D_ERROR("Could not initialize HG class.\n");
 		D_GOTO(out, rc = -DER_HG);
 	}
diff --git a/src/cart/crt_init.c b/src/cart/crt_init.c
index be43b8d1f1a..d66d99cd65c 100644
--- a/src/cart/crt_init.c
+++ b/src/cart/crt_init.c
@@ -1,5 +1,6 @@
 /*
  * (C) Copyright 2016-2024 Intel Corporation.
+ * (C) Copyright 2025 Hewlett Packard Enterprise Development LP
  *
  * SPDX-License-Identifier: BSD-2-Clause-Patent
  */
@@ -281,11 +282,17 @@ data_init(int server, crt_init_options_t *opt)
 		if (mem_pin_enable == 1)
 			mem_pin_workaround();
 	} else {
+		int retry_count = 3;
+
 		/*
 		 * Client-side envariable to indicate that the cluster
 		 * is running using a secondary provider
 		 */
 		crt_env_get(CRT_SECONDARY_PROVIDER, &is_secondary);
+
+		/** Client side env for hg_init() retries */
+		crt_env_get(CRT_CXI_INIT_RETRY, &retry_count);
+		crt_gdata.cg_hg_init_retry_cnt = retry_count;
 	}
 	crt_gdata.cg_provider_is_primary = (is_secondary) ? 0 : 1;
 
diff --git a/src/cart/crt_internal_types.h b/src/cart/crt_internal_types.h
index f10bf38d7c8..d35148c2bfe 100644
--- a/src/cart/crt_internal_types.h
+++ b/src/cart/crt_internal_types.h
@@ -1,5 +1,6 @@
 /*
  * (C) Copyright 2016-2024 Intel Corporation.
+ * (C) Copyright 2025 Hewlett Packard Enterprise Development LP
  *
  * SPDX-License-Identifier: BSD-2-Clause-Patent
  */
@@ -170,6 +171,8 @@ struct crt_gdata {
 	long			 cg_num_cores;
 	/** Inflight rpc quota limit */
 	uint32_t		cg_rpc_quota;
+	/** Retry count of HG_Init_opt2() on failure when using CXI provider */
+	uint32_t                 cg_hg_init_retry_cnt;
 };
 
 extern struct crt_gdata		crt_gdata;
@@ -197,6 +200,7 @@ struct crt_event_cb_priv {
 	ENV_STR(CRT_ATTACH_INFO_PATH)                                                              \
 	ENV(CRT_CREDIT_EP_CTX)                                                                     \
 	ENV(CRT_CTX_NUM)                                                                           \
+	ENV(CRT_CXI_INIT_RETRY)                                                                    \
 	ENV(CRT_ENABLE_MEM_PIN)                                                                    \
 	ENV_STR(CRT_L_GRP_CFG)                                                                     \
 	ENV(CRT_L_RANK)                                                                            \
diff --git a/src/container/srv_target.c b/src/container/srv_target.c
index 4ebe4aecd10..2718cbbc84a 100644
--- a/src/container/srv_target.c
+++ b/src/container/srv_target.c
@@ -1792,8 +1792,9 @@ ds_cont_tgt_open(uuid_t pool_uuid, uuid_t cont_hdl_uuid,
 		DP_UUID(pool_uuid), DP_UUID(cont_uuid), DP_UUID(cont_hdl_uuid));
 
 retry:
-	rc = ds_pool_thread_collective(pool_uuid, PO_COMP_ST_NEW | PO_COMP_ST_DOWN |
-				       PO_COMP_ST_DOWNOUT, cont_open_one, &arg, 0);
+	rc = ds_pool_thread_collective(pool_uuid,
+				       PO_COMP_ST_NEW | PO_COMP_ST_DOWN | PO_COMP_ST_DOWNOUT,
+				       cont_open_one, &arg, DSS_ULT_DEEP_STACK);
 	if (rc != 0) {
 		if (rc == -DER_AGAIN) {
 			dss_sleep(50);
@@ -2105,9 +2106,9 @@ ds_cont_tgt_snapshots_update(uuid_t pool_uuid, uuid_t cont_uuid,
 	 * the up targets in this scenario. The target property will be updated
 	 * upon initiating container aggregation.
 	 */
-	return ds_pool_thread_collective(pool_uuid, PO_COMP_ST_NEW | PO_COMP_ST_DOWN |
-					 PO_COMP_ST_DOWNOUT | PO_COMP_ST_UP,
-					 cont_snap_update_one, &args, 0);
+	return ds_pool_thread_collective(
+	    pool_uuid, PO_COMP_ST_NEW | PO_COMP_ST_DOWN | PO_COMP_ST_DOWNOUT | PO_COMP_ST_UP,
+	    cont_snap_update_one, &args, DSS_ULT_DEEP_STACK);
 }
 
 void
diff --git a/src/pool/srv_target.c b/src/pool/srv_target.c
index bd6ec4f9c11..3dccac41e1b 100644
--- a/src/pool/srv_target.c
+++ b/src/pool/srv_target.c
@@ -2256,8 +2256,9 @@ ds_pool_tgt_prop_update(struct ds_pool *pool, struct pool_iv_prop *iv_prop)
 		arg.uvp_checkpoint_props_changed = 1;
 	}
 
-	ret = ds_pool_thread_collective(pool->sp_uuid, PO_COMP_ST_DOWN | PO_COMP_ST_DOWNOUT |
-					PO_COMP_ST_NEW, update_vos_prop_on_targets, &arg, 0);
+	ret = ds_pool_thread_collective(pool->sp_uuid,
+					PO_COMP_ST_DOWN | PO_COMP_ST_DOWNOUT | PO_COMP_ST_NEW,
+					update_vos_prop_on_targets, &arg, DSS_ULT_DEEP_STACK);
 	if (ret != 0)
 		return ret;
 
diff --git a/utils/build.config b/utils/build.config
index fd34f7441e9..e90e4c8c7c6 100644
--- a/utils/build.config
+++ b/utils/build.config
@@ -27,6 +27,6 @@ ucx=https://github.com/openucx/ucx.git
 
 [patch_versions]
 spdk=https://github.com/spdk/spdk/commit/b0aba3fcd5aceceea530a702922153bc75664978.diff,https://github.com/spdk/spdk/commit/445a4c808badbad3942696ecf16fa60e8129a747.diff
-mercury=https://raw.githubusercontent.com/daos-stack/mercury/f3dc286fb40ec1a3a38a2e17c45497bc2aa6290d/na_ucx.patch
+mercury=https://raw.githubusercontent.com/daos-stack/mercury/f3dc286fb40ec1a3a38a2e17c45497bc2aa6290d/na_ucx.patch,https://raw.githubusercontent.com/daos-stack/mercury/48df263212604336b2dbe0430dcab4482eb43437/na_ucx_ep_flush.patch
 pmdk=https://github.com/pmem/pmdk/commit/2abe15ac0b4eed894b6768cd82a3b0a7c4336284.diff
 argobots=https://github.com/pmodels/argobots/pull/397/commits/411e5b344642ebc82190fd8b125db512e5b449d1.diff,https://github.com/pmodels/argobots/commit/bb0c908abfac4bfe37852eee621930634183c6aa.diff