--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/simtool/sysmo.c	Thu Feb 11 23:04:28 2021 +0000
@@ -0,0 +1,64 @@
+/*
+ * This module implements special commands for programmable and
+ * semi-programmable (made-up term for the version without ADM keys)
+ * SIM cards made by Sysmocom.
+ */
+
+#include <sys/types.h>
+#include <string.h>
+#include <strings.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "simresp.h"
+#include "curfile.h"
+#include "file_id.h"
+
+cmd_fix_sysmo_msisdn()
+{
+	int rc;
+	unsigned n;
+	u_char newrec[34];
+
+	rc = select_op(DF_TELECOM);
+	if (rc < 0)
+		return(rc);
+	rc = select_op(EF_MSISDN);
+	if (rc < 0)
+		return(rc);
+	rc = parse_ef_select_response();
+	if (rc < 0)
+		return(rc);
+	if (curfile_structure != 0x01) {
+		fprintf(stderr, "error: EF_MSISDN is not linear fixed\n");
+		return(-1);
+	}
+	if (curfile_record_len != 34) {
+		fprintf(stderr,
+		"error: expected EF_MSISDN record length of 34 bytes, got %u\n",
+			curfile_record_len);
+		return(-1);
+	}
+	rc = readrec_op(1, 0x04, 34);
+	if (rc < 0)
+		return(rc);
+	for (n = 0; n < 18; n++) {
+		if (sim_resp_data[n] != 0xFF) {
+			fprintf(stderr,
+		"error: non-FF data in the first 18 bytes of alpha tag area\n");
+			return(-1);
+		}
+	}
+	if (sim_resp_data[18] == 0xFF && sim_resp_data[19] == 0xFF) {
+		printf(
+		"last 2 bytes of alpha tag area are clear - already fixed?\n");
+		return(0);
+	}
+	if (sim_resp_data[18] != 0x07 || sim_resp_data[19] != 0x91) {
+		fprintf(stderr,
+	"error: bytes 18 & 19 don't match expected bogus programming\n");
+		return(-1);
+	}
+	memset(newrec, 0xFF, 34);
+	memcpy(newrec + 20, sim_resp_data + 18, 8);
+	return update_rec_op(1, 0x04, newrec, 34);
+}