diff --git a/adb/set_verity_enable_state_service.cpp b/adb/set_verity_enable_state_service.cpp
index 49e0363..253d14a 100644
--- a/adb/set_verity_enable_state_service.cpp
+++ b/adb/set_verity_enable_state_service.cpp
@@ -93,9 +93,21 @@
 /* Helper function to get A/B suffix, if any. If the device isn't
  * using A/B the empty string is returned. Otherwise either "_a",
  * "_b", ... is returned.
+ *
+ * Note that since sometime in O androidboot.slot_suffix is deprecated
+ * and androidboot.slot should be used instead. Since bootloaders may
+ * be out of sync with the OS, we check both and for extra safety
+ * prepend a leading underscore if there isn't one already.
  */
 static std::string get_ab_suffix() {
-    return android::base::GetProperty("ro.boot.slot_suffix", "");
+    std::string ab_suffix = android::base::GetProperty("ro.boot.slot_suffix", "");
+    if (ab_suffix == "") {
+        ab_suffix = android::base::GetProperty("ro.boot.slot", "");
+    }
+    if (ab_suffix.size() > 0 && ab_suffix[0] != '_') {
+        ab_suffix = std::string("_") + ab_suffix;
+    }
+    return ab_suffix;
 }
 
 /* Use AVB to turn verity on/off */
diff --git a/fs_mgr/fs_mgr_slotselect.cpp b/fs_mgr/fs_mgr_slotselect.cpp
index 33fd562..9ca15e2 100644
--- a/fs_mgr/fs_mgr_slotselect.cpp
+++ b/fs_mgr/fs_mgr_slotselect.cpp
@@ -21,12 +21,19 @@
 #include "fs_mgr.h"
 #include "fs_mgr_priv.h"
 
-// Returns "_a" or "_b" based on androidboot.slot_suffix in kernel cmdline, or an empty string
-// if that parameter does not exist.
+// Returns "_a" or "_b" based on two possible values in kernel cmdline:
+//   - androidboot.slot = a or b OR
+//   - androidboot.slot_suffix = _a or _b
+// TODO: remove slot_suffix once it's deprecated.
 std::string fs_mgr_get_slot_suffix() {
+    std::string slot;
     std::string ab_suffix;
 
-    fs_mgr_get_boot_config("slot_suffix", &ab_suffix);
+    if (fs_mgr_get_boot_config("slot", &slot)) {
+        ab_suffix = "_" + slot;
+    } else if (!fs_mgr_get_boot_config("slot_suffix", &ab_suffix)) {
+        ab_suffix = "";
+    }
     return ab_suffix;
 }