diff --git a/arch.mk b/arch.mk
index 5da39afa..a5a05f20 100644
--- a/arch.mk
+++ b/arch.mk
@@ -251,20 +251,33 @@ ifeq ($(ARCH),ARM)
     # MAX3266X TPU hardware SHA256 acceleration (requires MSDK_DIR)
     ifeq ($(MAX3266X_TPU),1)
       NO_ARM_ASM=1
-      CFLAGS+=-DWOLFSSL_MAX3266X -DMAX3266X_SHA
-      CFLAGS+=-DTARGET=MAX32665 -DTARGET_REV=0x4131
+      CFLAGS+=-DMAX3266X_SHA
       CFLAGS+=-ffunction-sections -fdata-sections
-      MAX3266X_CFLAGS:= \
-        -I$(MSDK_DIR)/Libraries/PeriphDrivers/Include/MAX32665/ \
-        -I$(MSDK_DIR)/Libraries/CMSIS/Device/Maxim/MAX32665/Include/ \
-        -I$(MSDK_DIR)/Libraries/PeriphDrivers/Source/TPU/ \
-        -I$(MSDK_DIR)/Libraries/PeriphDrivers/Source/SYS/ \
-        -I$(MSDK_DIR)/Libraries/CMSIS/Include/
-      CFLAGS+=$(MAX3266X_CFLAGS)
-      OBJS+=$(MSDK_DIR)/Libraries/PeriphDrivers/Source/TPU/tpu_me14.o \
-            $(MSDK_DIR)/Libraries/PeriphDrivers/Source/TPU/tpu_reva.o \
-            $(MSDK_DIR)/Libraries/PeriphDrivers/Source/SYS/sys_me14.o \
-            $(MSDK_DIR)/Libraries/PeriphDrivers/Source/SYS/mxc_delay.o
+      ifeq ($(MAX3266X_OLD),1)
+        # Older Maxim SDK tree (flat MAX32665PeriphDriver layout)
+        CFLAGS+=-DWOLFSSL_MAX3266X_OLD
+        MAX3266X_CFLAGS:= \
+          -I$(MSDK_DIR)/Libraries/MAX32665PeriphDriver/Include/ \
+          -I$(MSDK_DIR)/Libraries/CMSIS/Device/Maxim/MAX32665/Include/ \
+          -I$(MSDK_DIR)/Libraries/CMSIS/Include/
+        CFLAGS+=$(MAX3266X_CFLAGS)
+        OBJS+=$(MSDK_DIR)/Libraries/MAX32665PeriphDriver/Source/mxc_sys.o \
+              $(MSDK_DIR)/Libraries/MAX32665PeriphDriver/Source/mxc_delay.o
+      else
+        CFLAGS+=-DWOLFSSL_MAX3266X
+        CFLAGS+=-DTARGET=MAX32665 -DTARGET_REV=0x4131
+        MAX3266X_CFLAGS:= \
+          -I$(MSDK_DIR)/Libraries/PeriphDrivers/Include/MAX32665/ \
+          -I$(MSDK_DIR)/Libraries/CMSIS/Device/Maxim/MAX32665/Include/ \
+          -I$(MSDK_DIR)/Libraries/PeriphDrivers/Source/TPU/ \
+          -I$(MSDK_DIR)/Libraries/PeriphDrivers/Source/SYS/ \
+          -I$(MSDK_DIR)/Libraries/CMSIS/Include/
+        CFLAGS+=$(MAX3266X_CFLAGS)
+        OBJS+=$(MSDK_DIR)/Libraries/PeriphDrivers/Source/TPU/tpu_me14.o \
+              $(MSDK_DIR)/Libraries/PeriphDrivers/Source/TPU/tpu_reva.o \
+              $(MSDK_DIR)/Libraries/PeriphDrivers/Source/SYS/sys_me14.o \
+              $(MSDK_DIR)/Libraries/PeriphDrivers/Source/SYS/mxc_delay.o
+      endif
       WOLFCRYPT_OBJS+=$(WOLFBOOT_LIB_WOLFSSL)/wolfcrypt/src/port/maxim/max3266x.o
     endif
   endif
diff --git a/config/examples/max32666.config b/config/examples/max32666.config
index 7b090392..198e521c 100644
--- a/config/examples/max32666.config
+++ b/config/examples/max32666.config
@@ -10,6 +10,7 @@ NVM_FLASH_WRITEONCE?=1
 NO_MPU?=1
 DEBUG_UART?=1
 MAX3266X_TPU?=1
+MAX3266X_OLD?=0
 MSDK_DIR?=$(PWD)/../msdk
 WOLFBOOT_SECTOR_SIZE?=0x2000
 WOLFBOOT_PARTITION_SIZE?=0x40000
diff --git a/docs/Targets.md b/docs/Targets.md
index 8e3e48d9..ee658ac6 100644
--- a/docs/Targets.md
+++ b/docs/Targets.md
@@ -8623,6 +8623,8 @@ Boot success marked. Version: 1
 | `DEBUG_UART` | Enable UART0 debug output (115200 baud, 8N1). |
 | `EXT_FLASH` | Enable external flash support (for QSPI NAND configuration). |
 | `FLAGS_HOME` | Keep boot flags in internal flash (required when `EXT_FLASH=1`). |
+| `MAX3266X_TPU` | Enable TPU hardware SHA256 acceleration (requires `MSDK_DIR`). |
+| `MAX3266X_OLD` | Build TPU acceleration against the older, deprecated Maxim SDK tree instead of the modern MSDK. |
 
 ### MAX32666: External QSPI NAND Configuration