Using a Wireless Mini Keyboard.

A = Audio Delay Adj +/-
B = Timers
C = Context Menu (also Long Press OK, also Right Mouse Button)
D = n/a
E = EPG
F = FF (x2,x4,x8 etc)
G = n/a
H = Channels (List)
I = Info (Also M)
J = Radio Channels (List)
K = Recordings
L = n/a
M = Info (also I)
N = n/a
O = More Info
P = Play
Q = n/a
R = Rewind (-x2, -x4, -x8 etc)
S = Power Options
T = Subtitles
U = n/a
V = Choose Player
W = Watched Toggle
X = Stop Playback
Y = Choose Player
Z = n/a

Ctrl R = Instant Record

0 (zero) = Previous

Page Up-Page Down = Channel Up-Down
Number Keys select LCNs
Arrow Keys same as RCU
Enter = OK
F8 = Mute
F9 = Vol Down
F10 = Vol Up
ESC = Back, Ice Key, gets you out of submenus or back to the main Kodi menu.
SpaceBar = Wakeup (from suspend), also Pause + Timeshift Bar
Play,Pause,Stop (on the Rii Keyboard) as per the Ice RCU