Try this to fix the gamma screen.
"The quick steps are:
1. Go into Recovery Mode.
1.a. Turn off your Sansa.
1.b. Turn on the HOLD switch.
1.c. Hold the Record button down and push the power button. Don't let go of the Record button until you see "Welcome to Recovery Mode" on the screen.
1.d. Plug in the USB cable as directed.
2. Mount the drive.
2.a. If you have Windows, it'll show up as a USB Mass Storage Device automatically.
2.b. If you have Linux, you might have to mount it manually. (the device will be /dev/sda or /dev/sdb or something similar)
3. Copy over a patched bootloader.
3.a. You can get a working bootloader from
ftp://wisard.no-ip.com/pp5022.mi43.b. Copy ONLY the .mi4 file to the device.
4. Unmount and unplug.
4.a. In windows, stop the device with the "Safely remove hardware" option. In Linux, umount /dev/sda (or your device).
5. It will update the firmware and reboot. You should be able to boot both firmwares fine now (remember to turn HOLD off)."
-xoring