Okay, after a quick test:
* Visually, stuff looks fine on startup (Portrait, buttons on the right), menu is on top. However, touch coordinates are off in all Portrait orientation (touching the bottom-left corner registers on the top-right of the screen).
Touch input is okay in both Landscape orientations.
* Setting the frontlight crashes
Code:
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Os { code: 22, kind: InvalidInput, message: "Invalid argument" }', libcore/result.rs:1009:5
Never really played with that, but the ioctl used by Nickel seems identical as before:
Code:
[pid 180] 22:02:40 [7246e1f6] ioctl(13, _IOC(_IOC_NONE, 0, 0xf1, 0), 0x19) = 0
(@25%)
* Can't really say much about the FL warmth, as it's ineffectual with the FL @ 0, which, err, makes sense

.
* Button mapping appears to follow what you described, but it's a bit jarring compared to Nickel's mapping (i.e., it matches Nickel in Landscape, but not in Portrait).
* Gyro events behave properly.
* Rota:
Code:
1069:Framebuffer rotation: 2 -> 2.
1070:Framebuffer rotation: 3 -> 1.
1071:Framebuffer rotation: 1 -> 3.
1072:Framebuffer rotation: 2 -> 2.
1073:Framebuffer rotation: 3 -> 1.
1074:Framebuffer rotation: 0 -> 0.
1075:Framebuffer rotation: 1 -> 3.
1076:Framebuffer rotation: 0 -> 0.
1077:Framebuffer rotation: 3 -> 1.
1078:Framebuffer rotation: 0 -> 0.
1079:Framebuffer rotation: 3 -> 1.
1080:Framebuffer rotation: 2 -> 2.
1081:Framebuffer rotation: 1 -> 3.
1082:Framebuffer rotation: 0 -> 0.
1083:Framebuffer rotation: 1 -> 3.
1084:Framebuffer rotation: 2 -> 2.
1085:Framebuffer rotation: 3 -> 1.
1086:Framebuffer rotation: 2 -> 2.
1087:Framebuffer rotation: 1 -> 3.
1088:Framebuffer rotation: 2 -> 2.
1089:Framebuffer rotation: 3 -> 1.
1090:Framebuffer rotation: 2 -> 2.
1091:Framebuffer rotation: 1 -> 3.
1092:Framebuffer rotation: 0 -> 0.
1093:Framebuffer rotation: 1 -> 3.
1094:Framebuffer rotation: 2 -> 2.
1095:Framebuffer rotation: 3 -> 1.
1096:Framebuffer rotation: 2 -> 2.
1097:Framebuffer rotation: 1 -> 3.
1098:Framebuffer rotation: 2 -> 2.
1099:Framebuffer rotation: 0 -> 0.
1100:Framebuffer rotation: 2 -> 2.
1101:Framebuffer rotation: 3 -> 1.
1102:Framebuffer rotation: 1 -> 3.
Which matches my rota testcase.
* It's using the legacy MXCFB ioctls, not the Mk.7 ones.