diff --git a/sys/riscv/include/pte.h b/sys/riscv/include/pte.h
--- a/sys/riscv/include/pte.h
+++ b/sys/riscv/include/pte.h
@@ -102,6 +102,32 @@
 #define	PTE_MA_NC		(1ul << PTE_MA_SHIFT)
 #define	PTE_MA_IO		(2ul << PTE_MA_SHIFT)
 
+/*
+ * T-HEAD Custom Memory Attribute (MA) bits [63:59].
+ *
+ * bit 59: Trustable (relating to TEE)
+ * bit 60: Shareable (among CPUs, not configurable)
+ * bit 61: Bufferable (writes to device memory)
+ * bit 62: Cacheable
+ * bit 63: Memory Ordering (1 = strongly ordered (device), 0 = default)
+ *
+ * +------+-------+------------------------------------------------------------+
+ * | Mode | Value | Requested Memory Attributes                                |
+ * +------+-------+------------------------------------------------------------+
+ * | NC   | 00110 | Weakly-ordered, non-cacheable, bufferable, shareable,      |
+ * |      |       | non-trustable                                              |
+ * | PMA  | 01110 | Weakly-ordered, cacheable, bufferable, shareable,          |
+ * |      |       | non-trustable                                              |
+ * | IO   | 10010 | Strongly-ordered, non-cacheable, non-bufferable,           |
+ * |      |       | shareable, non-trustable                                   |
+ * +------+-------+------------------------------------------------------------+
+ */
+#define	PTE_THEAD_MA_SHIFT	59
+#define	PTE_THEAD_MA_MASK	(0x1ful << PTE_THEAD_MA_SHIFT)
+#define	PTE_THEAD_MA_NC		(0x6ul  << PTE_THEAD_MA_SHIFT)
+#define	PTE_THEAD_MA_NONE	(0xeul  << PTE_THEAD_MA_SHIFT)
+#define	PTE_THEAD_MA_IO		(0x12ul << PTE_THEAD_MA_SHIFT)
+
 /* Bits 63 - 54 are reserved for future use. */
 #define PTE_HI_MASK	0xFFC0000000000000ULL
 
diff --git a/sys/riscv/include/thead.h b/sys/riscv/include/thead.h
--- a/sys/riscv/include/thead.h
+++ b/sys/riscv/include/thead.h
@@ -30,6 +30,8 @@
 #ifndef _RISCV_THEAD_H_
 #define	_RISCV_THEAD_H_
 
+extern bool has_errata_thead_pbmt;
+
 void thead_setup_cache(void);
 
 #endif /* _RISCV_THEAD_H_ */
diff --git a/sys/riscv/riscv/identcpu.c b/sys/riscv/riscv/identcpu.c
--- a/sys/riscv/riscv/identcpu.c
+++ b/sys/riscv/riscv/identcpu.c
@@ -470,6 +470,7 @@
 	if (cpu != 0)
 		return;
 
+	has_errata_thead_pbmt = true;
 	thead_setup_cache();
 }
 
diff --git a/sys/riscv/riscv/pmap.c b/sys/riscv/riscv/pmap.c
--- a/sys/riscv/riscv/pmap.c
+++ b/sys/riscv/riscv/pmap.c
@@ -156,6 +156,7 @@
 #include <machine/md_var.h>
 #include <machine/pcb.h>
 #include <machine/sbi.h>
+#include <machine/thead.h>
 
 /*
  * Boundary values for the page table page index space:
@@ -867,6 +868,11 @@
 		memattr_bits[VM_MEMATTR_UNCACHEABLE] = PTE_MA_NC;
 		memattr_bits[VM_MEMATTR_DEVICE] = PTE_MA_IO;
 		memattr_mask = PTE_MA_MASK;
+	} else if (has_errata_thead_pbmt) {
+		memattr_bits[VM_MEMATTR_PMA] = PTE_THEAD_MA_NONE;
+		memattr_bits[VM_MEMATTR_UNCACHEABLE] = PTE_THEAD_MA_NC;
+		memattr_bits[VM_MEMATTR_DEVICE] = PTE_THEAD_MA_IO;
+		memattr_mask = PTE_THEAD_MA_MASK;
 	}
 
 	/* Create a new set of pagetables to run the kernel in. */
diff --git a/sys/riscv/thead/thead.c b/sys/riscv/thead/thead.c
--- a/sys/riscv/thead/thead.c
+++ b/sys/riscv/thead/thead.c
@@ -32,6 +32,8 @@
 
 #include <machine/thead.h>
 
+bool has_errata_thead_pbmt = false;
+
 /* ----------------- dcache ops --------------------- */
 
 /* MHTODO: we could parse this information from the device tree. */