1 files changed, 11 insertions, 25 deletions

diff --git a/firmware/lib/vboot_api_kernel.c b/firmware/lib/vboot_api_kernel.c
index 95507665..5f8eeaf9 100644
--- a/firmware/lib/vboot_api_kernel.c
+++ b/firmware/lib/vboot_api_kernel.c
@@ -183,31 +183,17 @@ vb2_error_t VbBootNormal(struct vb2_context *ctx)
 
 	VB2_DEBUG("Checking if TPM kernel version needs advancing\n");
 
-	if ((1 == shared->firmware_index) && (shared->flags & VBSD_FWB_TRIED)) {
-		/*
-		 * Special cases for when we're trying a new firmware B.  These
-		 * are needed because firmware updates also usually change the
-		 * kernel key, which means that the B firmware can only boot a
-		 * new kernel, and the old firmware in A can only boot the
-		 * previous kernel.
-		 *
-		 * Don't advance the TPM if we're trying a new firmware B,
-		 * because we don't yet know if the new kernel will
-		 * successfully boot.  We still want to be able to fall back to
-		 * the previous firmware+kernel if the new firmware+kernel
-		 * fails.
-		 *
-		 * If we found only invalid kernels, reboot and try again.
-		 * This allows us to fall back to the previous firmware+kernel
-		 * instead of giving up and going to recovery mode right away.
-		 * We'll still go to recovery mode if we run out of tries and
-		 * the old firmware can't find a kernel it likes.
-		 */
-		if (rv == VBERROR_INVALID_KERNEL_FOUND) {
-			VB2_DEBUG("Trying FW B; only found invalid kernels.\n");
-			VbSetRecoveryRequest(ctx, VB2_RECOVERY_NOT_REQUESTED);
-		}
-
+	/*
+	 * Special case for when we're trying a slot with new firmware.
+	 * Firmware updates also usually change the kernel key, which means
+	 * that the new firmware can only boot a new kernel, and the old
+	 * firmware in the previous slot can only boot the previous kernel.
+	 *
+	 * Don't roll-forward the kernel version, because we don't yet know if
+	 * the new kernel will successfully boot.
+	 */
+	if (vb2_nv_get(ctx, VB2_NV_FW_RESULT) == VB2_FW_RESULT_TRYING) {
+		VB2_DEBUG("Trying new FW; skip kernel version roll-forward.\n");
 		return rv;
 	}