diff --git a/repos/base-sel4/doc/notes.txt b/repos/base-sel4/doc/notes.txt
index 83e39344d..46024b4ea 100644
--- a/repos/base-sel4/doc/notes.txt
+++ b/repos/base-sel4/doc/notes.txt
@@ -789,6 +789,12 @@ lines:
 Since we modified the port-description file, we need to update the
 accompanied hash via './tool/ports/update_hash sel4'.
 
+_Edit: After consulting the seL4 mailing list, Adrian Danis pointed out that_
+_the actual issue is an off-by-one bug in the SEL4_FORCE_LONG_ENUM macro._
+_So instead of explicitly casting all opcodes to integers, the macro_
+_can be fixed at one place. Hence, I replaced the syscalls.patch by a_
+_macros.patch until the fix appears upstream._
+
 Anyway, after all the steps, our test-sel4 program can be successfully
 built. Executing the run script produces the result that we longed for:
 
diff --git a/repos/base-sel4/ports/sel4.hash b/repos/base-sel4/ports/sel4.hash
index 484dee7db..07b3b68bd 100644
--- a/repos/base-sel4/ports/sel4.hash
+++ b/repos/base-sel4/ports/sel4.hash
@@ -1 +1 @@
-39b692f97c6a83fdc35e22909b80ce804cc3aa84
+aaedf65867d799944024bab904c344c160069c0f
diff --git a/repos/base-sel4/ports/sel4.port b/repos/base-sel4/ports/sel4.port
index f93aacfea..2da589b9b 100644
--- a/repos/base-sel4/ports/sel4.port
+++ b/repos/base-sel4/ports/sel4.port
@@ -7,5 +7,5 @@ URL(sel4) := https://github.com/seL4/seL4.git
 REV(sel4) := b6fbb78cb1233aa8549ea3acb90524306f49a8d2
 DIR(sel4) := src/kernel/sel4
 
-PATCHES   := src/kernel/syscalls.patch
+PATCHES   := src/kernel/macros.patch
 PATCH_OPT := -p1 -d src/kernel/sel4
diff --git a/repos/base-sel4/src/kernel/macros.patch b/repos/base-sel4/src/kernel/macros.patch
new file mode 100644
index 000000000..27816dac5
--- /dev/null
+++ b/repos/base-sel4/src/kernel/macros.patch
@@ -0,0 +1,13 @@
+diff --git a/libsel4/include/sel4/macros.h b/libsel4/include/sel4/macros.h
+index 99b18e1..0eea3fb 100644
+--- a/libsel4/include/sel4/macros.h
++++ b/libsel4/include/sel4/macros.h
+@@ -17,7 +17,7 @@
+  * the same size as an 'int'.
+  */
+ #define SEL4_FORCE_LONG_ENUM(type) \
+-        _enum_pad_ ## type = (1U << ((sizeof(int)*8) - 1))
++        _enum_pad_ ## type = ((1U << ((sizeof(int)*8) - 1)) - 1)
+ 
+ #ifndef CONST
+ #define CONST        __attribute__((__const__))
diff --git a/repos/base-sel4/src/kernel/syscalls.patch b/repos/base-sel4/src/kernel/syscalls.patch
deleted file mode 100644
index 8c2083223..000000000
--- a/repos/base-sel4/src/kernel/syscalls.patch
+++ /dev/null
@@ -1,13 +0,0 @@
-diff --git a/libsel4/arch_include/ia32/sel4/arch/syscalls.h b/libsel4/arch_include/ia32/sel4/arch/syscalls.h
-index aef583b..d550343 100644
---- a/libsel4/arch_include/ia32/sel4/arch/syscalls.h
-+++ b/libsel4/arch_include/ia32/sel4/arch/syscalls.h
-@@ -475,7 +475,7 @@ seL4_DebugPutChar(char c)
-         "sysenter          \n"
-         "popl %%ebp        \n"
-         :
--        : "a" (seL4_SysDebugPutChar),
-+        : "a" ((int)seL4_SysDebugPutChar),
-         "b" (c)
-         : "%ecx", "%edx", "%esi", "%edi", "memory"
-     );