diff --git a/src/arch/riscv/scripts/sbi.lds b/src/arch/riscv/scripts/sbi.lds
index afb1902e1..f882f235e 100644
--- a/src/arch/riscv/scripts/sbi.lds
+++ b/src/arch/riscv/scripts/sbi.lds
@@ -5,10 +5,8 @@
 
 SECTIONS {
 
-    /* Start at virtual address zero */
-    . = 0;
-
     /* Weak symbols that need zero values if not otherwise defined */
+    saved_pos = .;
     .weak 0x0 : {
 	_weak = .;
 	*(.weak)
@@ -16,6 +14,7 @@ SECTIONS {
 	_eweak = .;
     }
     _assert = ASSERT ( ( _weak == _eweak ), ".weak is non-zero length" );
+    _assert = ASSERT ( ( . == saved_pos ), ".weak altered current position" );
 
     /* Prefix code */
     .prefix : {
@@ -105,7 +104,7 @@ SECTIONS {
     _ereloc = ( _reloc + __load_stop_reladyn - __load_start_reladyn );
 
     /* Length of initialised data */
-    _sbi_filesz = ABSOLUTE ( _ereloc );
+    _sbi_filesz = ( ABSOLUTE ( _ereloc ) - ABSOLUTE ( _prefix ) );
 
     /* Unwanted sections */
     /DISCARD/ : {
diff --git a/src/arch/riscv32/Makefile.sbi b/src/arch/riscv32/Makefile.sbi
index d62287770..5841dd4b5 100644
--- a/src/arch/riscv32/Makefile.sbi
+++ b/src/arch/riscv32/Makefile.sbi
@@ -1,5 +1,13 @@
 # -*- makefile -*- : Force emacs to use Makefile mode
 
+# Set base virtual address to 0xeb000000
+#
+# This is aligned to a 4MB boundary and so allows 4MB megapages to be
+# used to map the iPXE binary.  The address pattern is also easily
+# recognisable if leaked to unexpected contexts.
+#
+LDFLAGS		+= --section-start=.prefix=0xeb000000
+
 # Include generic SBI Makefile
 #
 MAKEDEPS	+= arch/riscv/Makefile.sbi
diff --git a/src/arch/riscv64/Makefile.sbi b/src/arch/riscv64/Makefile.sbi
index d62287770..0f7e1c373 100644
--- a/src/arch/riscv64/Makefile.sbi
+++ b/src/arch/riscv64/Makefile.sbi
@@ -1,5 +1,13 @@
 # -*- makefile -*- : Force emacs to use Makefile mode
 
+# Set base virtual address to 0xffffffffeb000000
+#
+# This is aligned to a 2MB boundary and so allows 2MB megapages to be
+# used to map the iPXE binary.  The address pattern is also easily
+# recognisable if leaked to unexpected contexts.
+#
+LDFLAGS		+= --section-start=.prefix=0xffffffffeb000000
+
 # Include generic SBI Makefile
 #
 MAKEDEPS	+= arch/riscv/Makefile.sbi