LedgerHQ · nroggeman-ledger · Feb 16, 2026 · Feb 16, 2026 · Feb 16, 2026 · Feb 17, 2026
diff --git a/fuzzing/mock/custom/mocks.c b/fuzzing/mock/custom/mocks.c
@@ -74,3 +74,10 @@ void mainExit(int exitCode)
 {
     (void) exitCode;
 }
+
+unsigned int os_sched_current_task(void);
+
+unsigned int os_sched_current_task(void)
+{
+    return TASK_USER;
+}
diff --git a/fuzzing/shared_libs/libnbgl_shared_apex_p.a b/fuzzing/shared_libs/libnbgl_shared_apex_p.a
diff --git a/fuzzing/shared_libs/libnbgl_shared_flex.a b/fuzzing/shared_libs/libnbgl_shared_flex.a
diff --git a/fuzzing/shared_libs/libnbgl_shared_nanosp.a b/fuzzing/shared_libs/libnbgl_shared_nanosp.a
diff --git a/fuzzing/shared_libs/libnbgl_shared_nanox.a b/fuzzing/shared_libs/libnbgl_shared_nanox.a
diff --git a/fuzzing/shared_libs/libnbgl_shared_stax.a b/fuzzing/shared_libs/libnbgl_shared_stax.a
diff --git a/include/os_task.h b/include/os_task.h
@@ -10,18 +10,9 @@ typedef unsigned char bolos_task_status_t;
 enum task_unsecure_id_e {
     TASK_BOLOS = 0,  // can call os
     TASK_SYSCALL,    // can call os
-    TASK_USERTASKS_START,
-    // disabled for now // TASK_USER_UX, // must call syscalls to reach os, locked in ux ram
-    TASK_USER = TASK_USERTASKS_START,  // must call syscalls to reach os, locked in app ram
-    TASK_SUBTASKS_START,
-    TASK_SUBTASK_0 = TASK_SUBTASKS_START,
-#ifdef TARGET_NANOX
-    TASK_SUBTASK_1,
-    TASK_SUBTASK_2,
-    TASK_SUBTASK_3,
-#endif  // TARGET_NANOX
-    TASK_BOLOS_UX,
-    TASK_MAXCOUNT,  // must be last in the structure
+    TASK_USER,       // must call syscalls to reach os, locked in app ram
+    TASK_BOLOS_UX,   // must call syscalls to reach os
+    TASK_MAXCOUNT    // must be last in the structure
 };
 
 // exit the current task
@@ -31,54 +22,7 @@ SYSCALL void os_sched_exit(bolos_task_status_t exit_code);
 SYSCALL void __attribute__((noreturn)) os_sched_exit(bolos_task_status_t exit_code);
 #endif
 
-// returns true when the given task is running, false else.
-SYSCALL bolos_bool_t os_sched_is_running(unsigned int task_idx);
-
 /**
  * Retrieve the last status issued by a task using either yield or exit.
  */
 SUDOCALL bolos_task_status_t os_sched_last_status(unsigned int task_idx);
-
-/**
- * Current task is yielding the process to another task.
- * Meta call for task_switch with 'the enxt' task idx.
- * @param status is the current task status
- */
-SUDOCALL TASKSWITCH void os_sched_yield(bolos_task_status_t status);
-
-/**
- * Perform task switching
- * @param task_idx is the task index to switch to
- * @param status of the currently executed task
- * @return the status of the previously running task
- */
-SUDOCALL TASKSWITCH void os_sched_switch(unsigned int task_idx, bolos_task_status_t status);
-
-/**
- * Function that returns the currently running task identifier.
- */
-SUDOCALL unsigned int os_sched_current_task(void);
-
-/**
- * Create a new task with the given parameters and return its task identifier.
- * The newly created task is chrooted in the given nvram/ram1/ram2 segments
- * and its task pointer is set at the end of ram1 segment.
- * The task is bound to the currently running application.
- * The task identifiers are not guaranteed to be the same after a power cycle.
- * At least valid main, nvram segment, ram0 segment and stack segment must be provided with.
- * @param main The main function address to start the task with.
- * @param nvram The nvram segment address start
- * @param nvram_length The nvram segment length
- * @param ram0 /ram0_length the first RAM segment description
- * @param stack /stack_length the task's stack RAM segment description
- */
-SYSCALL unsigned int os_sched_create(void *main   PLENGTH(4),
-                                     void *nvram  PLENGTH(nvram_length),
-                                     unsigned int nvram_length,
-                                     void *ram0   PLENGTH(ram0_length),
-                                     unsigned int ram0_length,
-                                     void *stack  PLENGTH(stack_length),
-                                     unsigned int stack_length);
-
-// kill a task
-SYSCALL void os_sched_kill(unsigned int taskidx);
diff --git a/include/os_ux.h b/include/os_ux.h
@@ -84,8 +84,6 @@ void bolos_test_ux_apdu(void);
 // is not processed. when returning !0 the application must send a general status (or continue its
 // command flow)
 SYSCALL TASKSWITCH unsigned int os_ux(bolos_ux_params_t *params PLENGTH(sizeof(bolos_ux_params_t)));
-// read parameters back from the UX app. useful to read keyboard type or such
-SYSCALL void os_ux_result(bolos_ux_params_t *params PLENGTH(sizeof(bolos_ux_params_t)));
 
 // process all possible messages while waiting for a ux to finish,
 // unprocessed messages are replied with a generic general status

diff --git a/include/syscalls.h b/include/syscalls.h
@@ -182,9 +182,7 @@
 #define SYSCALL_RESERVED_6_ID                              0x00000125
 #define SYSCALL_RESERVED_34_ID                             0x01000126
 #define SYSCALL_os_sched_exit_ID                           0x0100009a
-#define SYSCALL_os_sched_is_running_ID                     0x0100009b
-#define SYSCALL_os_sched_create_ID                         0x0700011b
-#define SYSCALL_os_sched_kill_ID                           0x01000078
+#define SYSCALL_RESERVED_36_ID                             0x0100009b
 #define SYSCALL_os_io_seph_tx_ID                           0x03000082
 #define SYSCALL_os_io_seph_se_rx_event_ID                  0x05000083
 #define SYSCALL_os_io_init_ID                              0x01000084
@@ -197,9 +195,9 @@
 #define SYSCALL_try_context_get_ID                         0x00000087
 #define SYSCALL_try_context_set_ID                         0x0100010b
 #define SYSCALL_os_sched_last_status_ID                    0x0100009c
-#define SYSCALL_os_sched_yield_ID                          0x0100009d
+#define SYSCALL_RESERVED_38_ID                             0x0100009d
 #define SYSCALL_os_sched_switch_ID                         0x0200009e
-#define SYSCALL_os_sched_current_task_ID                   0x0000008b
+#define SYSCALL_RESERVED_37_ID                             0x0000008b
 #define SYSCALL_os_allow_protected_flash_ID                0x0000008e
 #define SYSCALL_os_deny_protected_flash_ID                 0x00000091
 #define SYSCALL_os_allow_protected_ram_ID                  0x00000092

diff --git a/src/syscalls.c b/src/syscalls.c
@@ -1533,42 +1533,6 @@ void __attribute__((noreturn)) os_sched_exit(bolos_task_status_t exit_code)
     __builtin_unreachable();
 }
 
-bolos_bool_t os_sched_is_running(unsigned int task_idx)
-{
-    unsigned int parameters[2];
-    parameters[0] = (unsigned int) task_idx;
-    parameters[1] = 0;
-    return (bolos_bool_t) SVC_Call(SYSCALL_os_sched_is_running_ID, parameters);
-}
-
-unsigned int os_sched_create(void        *main,
-                             void        *nvram,
-                             unsigned int nvram_length,
-                             void        *ram0,
-                             unsigned int ram0_length,
-                             void        *stack,
-                             unsigned int stack_length)
-{
-    unsigned int parameters[7];
-    parameters[0] = (unsigned int) main;
-    parameters[1] = (unsigned int) nvram;
-    parameters[2] = (unsigned int) nvram_length;
-    parameters[3] = (unsigned int) ram0;
-    parameters[4] = (unsigned int) ram0_length;
-    parameters[5] = (unsigned int) stack;
-    parameters[6] = (unsigned int) stack_length;
-    return (unsigned int) SVC_Call(SYSCALL_os_sched_create_ID, parameters);
-}
-
-void os_sched_kill(unsigned int taskidx)
-{
-    unsigned int parameters[2];
-    parameters[0] = (unsigned int) taskidx;
-    parameters[1] = 0;
-    SVC_Call(SYSCALL_os_sched_kill_ID, parameters);
-    return;
-}
-
 int os_io_seph_tx(const unsigned char *buffer, unsigned short length, unsigned int *timeout_ms)
 {
     unsigned int parameters[3];
@@ -1680,31 +1644,6 @@ bolos_task_status_t os_sched_last_status(unsigned int task_idx)
     return (bolos_task_status_t) SVC_Call(SYSCALL_os_sched_last_status_ID, parameters);
 }
 
-void os_sched_yield(bolos_task_status_t status)
-{
-    unsigned int parameters[2];
-    parameters[0] = (unsigned int) status;
-    parameters[1] = 0;
-    SVC_Call(SYSCALL_os_sched_yield_ID, parameters);
-    return;
-}
-
-void os_sched_switch(unsigned int task_idx, bolos_task_status_t status)
-{
-    unsigned int parameters[2];
-    parameters[0] = (unsigned int) task_idx;
-    parameters[1] = (unsigned int) status;
-    SVC_Call(SYSCALL_os_sched_switch_ID, parameters);
-    return;
-}
-
-unsigned int os_sched_current_task(void)
-{
-    unsigned int parameters[2];
-    parameters[1] = 0;
-    return (unsigned int) SVC_Call(SYSCALL_os_sched_current_task_ID, parameters);
-}
-
 unsigned int os_allow_protected_ram(void)
 {
     unsigned int parameters[2];

diff --git a/tests/screenshots/shared_libs/libnbgl_shared_screenshots_apex_p.a b/tests/screenshots/shared_libs/libnbgl_shared_screenshots_apex_p.a
diff --git a/tests/screenshots/shared_libs/libnbgl_shared_screenshots_flex.a b/tests/screenshots/shared_libs/libnbgl_shared_screenshots_flex.a
diff --git a/tests/screenshots/shared_libs/libnbgl_shared_screenshots_nanosp.a b/tests/screenshots/shared_libs/libnbgl_shared_screenshots_nanosp.a
diff --git a/tests/screenshots/shared_libs/libnbgl_shared_screenshots_nanox.a b/tests/screenshots/shared_libs/libnbgl_shared_screenshots_nanox.a
diff --git a/tests/screenshots/shared_libs/libnbgl_shared_screenshots_stax.a b/tests/screenshots/shared_libs/libnbgl_shared_screenshots_stax.a
diff --git a/tests/screenshots/src/main/stubs.c b/tests/screenshots/src/main/stubs.c
@@ -237,6 +237,8 @@ void os_sched_exit(bolos_task_status_t status_code)
     exit(-1);
 }
 
+unsigned int os_sched_current_task(void);
+
 unsigned int os_sched_current_task(void)
 {
     return TASK_USER;