Index: head/sys/riscv/include/machdep.h
===================================================================
--- head/sys/riscv/include/machdep.h
+++ head/sys/riscv/include/machdep.h
@@ -42,6 +42,7 @@
 	vm_offset_t	kern_phys;	/* Kernel base (physical) addr */
 	vm_offset_t	kern_stack;
 	vm_offset_t	dtbp_virt;	/* Device tree blob virtual addr */
+	vm_offset_t	dtbp_phys;	/* Device tree blob physical addr */
 };
 
 extern vm_paddr_t physmap[PHYS_AVAIL_ENTRIES];
Index: head/sys/riscv/riscv/genassym.c
===================================================================
--- head/sys/riscv/riscv/genassym.c
+++ head/sys/riscv/riscv/genassym.c
@@ -106,3 +106,4 @@
 ASSYM(RISCV_BOOTPARAMS_KERN_STACK, offsetof(struct riscv_bootparams,
     kern_stack));
 ASSYM(RISCV_BOOTPARAMS_DTBP_VIRT, offsetof(struct riscv_bootparams, dtbp_virt));
+ASSYM(RISCV_BOOTPARAMS_DTBP_PHYS, offsetof(struct riscv_bootparams, dtbp_phys));
Index: head/sys/riscv/riscv/locore.S
===================================================================
--- head/sys/riscv/riscv/locore.S
+++ head/sys/riscv/riscv/locore.S
@@ -221,6 +221,7 @@
 	and	t1, a1, t1
 	add	t0, t0, t1
 	sd	t0, RISCV_BOOTPARAMS_DTBP_VIRT(sp)
+	sd	a1, RISCV_BOOTPARAMS_DTBP_PHYS(sp)
 
 	mv	a0, sp
 	call	_C_LABEL(initriscv)	/* Off we go */
Index: head/sys/riscv/riscv/machdep.c
===================================================================
--- head/sys/riscv/riscv/machdep.c
+++ head/sys/riscv/riscv/machdep.c
@@ -776,8 +776,19 @@
 	PRELOAD_PUSH_VALUE(uint32_t, 0);
 	preload_metadata = (caddr_t)fake_preload;
 
+	/* Check if bootloader clobbered part of the kernel with the DTB. */
+	KASSERT(rvbp->dtbp_phys + dtb_size <= rvbp->kern_phys ||
+		rvbp->dtbp_phys >= rvbp->kern_phys + (lastaddr - KERNBASE),
+	    ("FDT (%lx-%lx) and kernel (%lx-%lx) overlap", rvbp->dtbp_phys,
+		rvbp->dtbp_phys + dtb_size, rvbp->kern_phys,
+		rvbp->kern_phys + (lastaddr - KERNBASE)));
 	KASSERT(fake_size < sizeof(fake_preload),
 	    ("Too many fake_preload items"));
+
+	if (boothowto & RB_VERBOSE)
+		printf("FDT phys (%lx-%lx), kernel phys (%lx-%lx)\n",
+		    rvbp->dtbp_phys, rvbp->dtbp_phys + dtb_size,
+		    rvbp->kern_phys, rvbp->kern_phys + (lastaddr - KERNBASE));
 
 	return (lastaddr);
 }