diff --git a/TODO.md b/TODO.md
index 2694c09..5ce62e1 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,4 +1,4 @@
-* Handle "_msi64bit1" addresses.
+* Handle "_msi64bit1" addresses (error message "ValueError: invalid literal.*" gives more details).
 * Handle MSRs and mark them specially (error message "ERROR unrolling: logical instances are.*MSR.*impossible" gives more details)
 * Handle HOSTSWUS.*PCIEs and mark them specially (error message "ERROR unrolling: logical instances are.*PCIE.*impossible" gives more details)
 * Some PCIInfo blocks are not yet grouped.  Add settings to settings.py.  Find them by: grep VENDOR_ID.*unsorted phase4_host.svd  |wc -l: HOST: 68 (DEVICE_VENDOR_ID: 24); SMN: 142 (DEVICE_VENDOR_ID: 28)