With this tool you can enter in recovery mode easily without adding your udid instead of the initial code from Libimobiledevice

ideviceenterrecovery.c

/* gcc ideviceenterrecovery.c -o ideviceenterrecovery -limobiledevice */
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

#include <libimobiledevice/libimobiledevice.h>
#include <libimobiledevice/lockdown.h>

static char *udid = NULL;
int main()
{
        idevice_error_t ret = IDEVICE_E_UNKNOWN_ERROR;
        idevice_t device = NULL;
        lockdownd_client_t client = NULL;
        lockdownd_error_t ldret = LOCKDOWN_E_UNKNOWN_ERROR;

        if (IDEVICE_E_SUCCESS != idevice_new(&device, NULL))
    {
        printf("No device found, is it plugged in?\n");
        return EXIT_FAILURE;
    }
    ret = idevice_get_udid(device, &udid);
        printf("Telling device with udid %s to enter recovery mode.\n", udid);

        if (LOCKDOWN_E_SUCCESS != (ldret = lockdownd_client_new(device, &client, "ideviceenterrecovery"))) {
                printf("ERROR: Could not connect to lockdownd, error code %d\n", ldret);
                idevice_free(device);
                return -1;
        }

        if (lockdownd_enter_recovery(client) != LOCKDOWN_E_SUCCESS)
        {
                printf("Failed to enter recovery mode : %s\n", strerror(errno));
                exit(1);
        }

        printf("Device is switching to recovery mode.\n");

        lockdownd_client_free(client);
        idevice_free(device);

        return 0;
}