M.2 solid-state drive . . . . . . . . . . . 53
WWAN card (for selected models) . . . . . . 56
Keyboard (for ThinkPad X390 only) . . . . . 58
Chapter 8. Help and support . . . . . 65
Frequently asked questions . . . . . . . . . . 65
Error messages . . . . . . . . . . . . . . . 66
Beep errors . . . . . . . . . . . . . . . . 68
Self-help resources . . . . . . . . . . . . . 69
Call Lenovo . . . . . . . . . . . . . . . . 70
Before you contact Lenovo . . . . . . . . 70
Lenovo Customer Support Center . . . . . . 71
Purchase additional services. . . . . . . . . . 72
Appendix A. Important safety
information . . . . . . . . . . . . . . . 73
Appendix B. Accessibility and
ergonomic information . . . . . . . . 87
Appendix C. Supplemental
information about the Linux operating
system . . . . . . . . . . . . . . . . . 91
Appendix D. Compliance
information . . . . . . . . . . . . . . . 93
Appendix E. Notices and
trademarks . . . . . . . . . . . . . . . 107
ii T490s and X390 User Guide
