diff --git a/repos/base-hw/lib/mk/spec/riscv/bootstrap-hw.mk b/repos/base-hw/lib/mk/spec/riscv/bootstrap-hw.mk
index a36ecd166..94d027d9b 100644
--- a/repos/base-hw/lib/mk/spec/riscv/bootstrap-hw.mk
+++ b/repos/base-hw/lib/mk/spec/riscv/bootstrap-hw.mk
@@ -1,4 +1,10 @@
-INC_DIR += $(BASE_DIR)/../base-hw/src/bootstrap/spec/riscv
+#
+# evaluate bbl_dir immediately, otherwise it won't recognize
+# missing ports when checking library dependencies
+#
+BBL_DIR := $(call select_from_ports,bbl)/src/lib/bbl
+
+INC_DIR += $(BASE_DIR)/../base-hw/src/bootstrap/spec/riscv $(BBL_DIR)
 
 SRC_CC  += bootstrap/spec/riscv/platform.cc
 SRC_CC  += lib/base/riscv/kernel/interface.cc
diff --git a/repos/base-hw/lib/mk/spec/riscv/core-hw.mk b/repos/base-hw/lib/mk/spec/riscv/core-hw.mk
index fe940bcd7..97d7cc3ba 100644
--- a/repos/base-hw/lib/mk/spec/riscv/core-hw.mk
+++ b/repos/base-hw/lib/mk/spec/riscv/core-hw.mk
@@ -1,4 +1,10 @@
-INC_DIR += $(REP_DIR)/src/core/spec/riscv
+#
+# evaluate bbl_dir immediately, otherwise it won't recognize
+# missing ports when checking library dependencies
+#
+BBL_DIR := $(call select_from_ports,bbl)/src/lib/bbl
+
+INC_DIR += $(REP_DIR)/src/core/spec/riscv $(BBL_DIR)
 
 CC_OPT += -fno-delete-null-pointer-checks
 
diff --git a/repos/base-hw/ports/bbl.hash b/repos/base-hw/ports/bbl.hash
index 010c8043b..2f836aba2 100644
--- a/repos/base-hw/ports/bbl.hash
+++ b/repos/base-hw/ports/bbl.hash
@@ -1 +1 @@
-30243a733d49c8545adbb230df7e01f8a8fc12a0
+b9358ccd68ac9fbb0ea49b22aa4dd08fdaae1978
diff --git a/repos/base-hw/ports/bbl.port b/repos/base-hw/ports/bbl.port
index 1476e0984..c2bd6e2de 100644
--- a/repos/base-hw/ports/bbl.port
+++ b/repos/base-hw/ports/bbl.port
@@ -3,6 +3,6 @@ VERSION   := git
 DOWNLOADS := bbl.git
 
 URL(bbl) = https://github.com/skalk/bbl-lite.git
-REV(bbl) = 20e03dfa317747dd39175f9fc3c15c50b702ac04
+REV(bbl) = 22300f2f0ea72b7f9228ca6743d4ebb12cf5a79b
 DIR(bbl) = src/lib/bbl
 
diff --git a/repos/base-hw/src/lib/hw/spec/riscv/machine_call.h b/repos/base-hw/src/lib/hw/spec/riscv/machine_call.h
index d0b95be33..49523a73e 100644
--- a/repos/base-hw/src/lib/hw/spec/riscv/machine_call.h
+++ b/repos/base-hw/src/lib/hw/spec/riscv/machine_call.h
@@ -16,41 +16,33 @@
 #ifndef _SRC__LIB__HW__SPEC__RISCV__MACHINE_CALL_H_
 #define _SRC__LIB__HW__SPEC__RISCV__MACHINE_CALL_H_
 
-#include <kernel/interface.h>
+using uintptr_t = unsigned long;
+#include <bbl/mcall.h>
 
 namespace Hw {
-	using Kernel::addr_t;
-	using Kernel::Call_arg;
-	using Genode::uint64_t;
 
-	/**
-	 * SBI calls to machine mode.
-	 *
-	 * Keep in sync with exception_vector.s.
-	 */
-	constexpr Call_arg call_id_set_sys_timer() { return 200; }
-	constexpr Call_arg call_id_get_sys_timer() { return 201; }
-
-	inline addr_t ecall(addr_t call, addr_t arg)
+	inline unsigned long ecall(unsigned long id, unsigned long a0,
+	                           unsigned long a1)
 	{
 		asm volatile ("mv a0, %0\n"
 		              "mv a1, %1\n"
+		              "mv a2, %2\n"
 		              "ecall    \n"
 		              "mv %0, a0\n"
-		              :  "+r"(call) : "r"(arg)
-		              : "a0", "a1");
-		return call;
+		              :  "+r"(id) : "r"(a0), "r"(a1)
+		              : "a0", "a1", "a2");
+		return id;
 	}
 
-	inline void put_char(addr_t c) {
-		ecall(Kernel::call_id_print_char(), c);
+	inline void put_char(unsigned long c) {
+		ecall(MCALL_CONSOLE_PUTCHAR, c, /* unused arg */ 0);
 	}
 
-	inline void set_sys_timer(addr_t t) {
-		Kernel::call(call_id_set_sys_timer(), (Call_arg)t); }
+	inline void set_sys_timer(unsigned long t) {
+		ecall(MCALL_SET_TIMER, t, /* unused arg */ 0); }
 
-	inline addr_t get_sys_timer() {
-		return Kernel::call(call_id_get_sys_timer()); }
+	inline unsigned long get_sys_timer() {
+		return ecall(MCALL_GET_TIMER, /* unused args */ 0, 0); }
 }
 
 #endif /* _SRC__LIB__HW__SPEC__RISCV__MACHINE_CALL_H_ */