spruce up the 820 g2 page a bit more

Signed-off-by: Leah Rowe <leah@libreboot.org>

site/docs/hardware/hp820g2.md

@@ -73,6 +73,16 @@ This is a beastly 12.5" Broadwell machine from HP, the main benefit of which is
 high power efficiency (compared to Ivybridge and Haswell platforms), while
 offering similar CPU performance but much higher graphics performance.
 
+Variants exist with either Intel Core i5-5200U, i5-5300U, i7-5500U or
+i7-5600U and it comes with a plethora of ports; 3x USB 3.0, DisplayPort (which
+can do 4K 60Hz), a VGA port, can be expanded to 32GB RAM, has *3* slots which
+can take SSDs (PCIe, M2 and regular SATA), also has a side dock connector (for
+a docking station). The screen is eDP type and can be upgraded to 1920x1080.
+
+This is a nice portable machine, with very reasonable performance. Most people
+should be very satisfied with it, in daily use. It is widely available in
+online market places. This page will tell you how to flash it!
+
 All variants of this mainboard will come with Intel HD 5500 graphics, which has
 completely free software initialisation in coreboot, provided by *libgfxinit*.
 
@@ -288,6 +298,18 @@ a backup of both flash ICs, just in case (dumped using `-r` in flashrom).
 And that's all. Refer to other documents on Libreboot's website for how
 to handle Linux/BSD systems and generally use your machine.
 
+TPM 2.0 potentially supported
+==============================
+
+The onboard TPM is an SLB 9660, which supports TPM 1.2 but it is known to be
+compatible with TPM 2.0 via firmware upgrade. Although not yet tested, we have
+some notes about that here:
+
+[../../tasks/#hp-820-g2-tpm](../../tasks/#hp-820-g2-tpm)
+
+Not yet used meaningfully by Libreboot itself, but the TPM can be used to
+implement things like measured boot.
+
 References
 ==========