flashrom.8: add missing entry for `--flash-contents`

Change-Id: I64a8200a86329bd26a2069c5dc39430de9f8ba09
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/57807
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/67856
Reviewed-by: Felix Singer <felixsinger@posteo.net>
---
M flashrom.8.tmpl
1 file changed, 22 insertions(+), 0 deletions(-)

diff --git a/flashrom.8.tmpl b/flashrom.8.tmpl
index c1a228b..5192d0b 100644
--- a/flashrom.8.tmpl
+++ b/flashrom.8.tmpl
@@ -242,6 +242,13 @@
 .B <imagename>
 from flash layout.
 .TP
+.B "\-\-flash\-contents <ref\-file>"
+The file contents of
+.BR <ref\-file>
+will be used to decide which parts of the flash need to be written. Providing
+this saves an initial read of the full flash chip. Be careful, if the provided
+data doesn't actually match the flash contents, results are undefined.
+.TP
 .B "\-L, \-\-list\-supported"
 List the flash chips, chipsets, mainboards, and external programmers
 (including PCI, USB, parallel port, and serial port based devices)

