I know this is an old thread, but I figured out how to get this working using the GSPLUS emulator. You'll need to create a .gsp file for Flobynoid. I used the sd71 slot and followed the path to another version of the Flobynoid rom with a .po extension. I also used an apple2gs.rom1 when I picked the ROM file. It will run Flobynoid in GS Mode when you do this.

Here is what my .gsp file looks like:

GSplus configuration file version 0.14

s5d1 =
s5d2 =

s6d1 =
s6d2 =

s7d1 = /home/pi/RetroPie/roms/APPLE2GS/Flobynoid.po

g_joystick_scale_factor_x = 281
g_joystick_scale_factor_y = 281
g_cfg_rom_path = ../../../../home/pi/RetroPie/roms/apple2gs/APPLE2GS.ROM1

bram1[00] = 00 00 00 01 00 00 0d 06 02 01 01 00 01 00 00 00
bram1[10] = 00 00 07 06 02 01 01 00 00 00 0f 06 06 00 05 06
bram1[20] = 01 00 00 00 00 00 00 01 00 00 00 00 03 02 02 02
bram1[30] = 00 00 00 00 00 00 00 00 08 00 01 02 03 04 05 06
bram1[40] = 07 0a 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d
bram1[50] = 0e 0f ff ff ff ff ff ff ff ff ff ff ff ff ff 81
bram1[60] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram1[70] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram1[80] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram1[90] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram1[a0] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram1[b0] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram1[c0] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram1[d0] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram1[e0] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram1[f0] = ff ff ff ff ff ff ff ff ff ff ff ff 52 04 f8 ae

bram3[00] = 00 00 00 01 00 00 0d 06 02 01 01 00 01 00 00 00
bram3[10] = 00 00 07 06 02 01 01 00 00 00 0f 06 06 00 05 06
bram3[20] = 01 00 00 00 00 00 00 01 00 00 00 00 05 02 02 00
bram3[30] = 00 00 2d 2d 00 00 00 00 00 00 02 02 02 06 08 00
bram3[40] = 01 02 03 04 05 06 07 0a 00 01 02 03 04 05 06 07
bram3[50] = 08 09 0a 0b 0c 0d 0e 0f 00 00 ff ff ff ff ff ff
bram3[60] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram3[70] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram3[80] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram3[90] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram3[a0] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram3[b0] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram3[c0] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram3[d0] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram3[e0] = ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
bram3[f0] = ff ff ff ff ff ff ff ff ff ff ff ff 36 2d 9c 87

As far as the BIOS roms go, I could never find the correct apple2.zip, so I copied the set of Apple II roms that were included in a build of Batocera I am currently using with my Pi5. I'm going to replace that with RetroPie once the experts here get around to creating a stable build, but I thought I'd share my solution here for those who want to try Flobynoid with GSPLUS.

(Solved) Linapple exits when pressing f3 or f4