Luma3DS-updater in lpp-3ds

local white = Color.new(255,255,255)
local url = "http://astronautlevel2.github.io/Luma3DS/latest.zip"
local zip_path = "/latest.zip"
local a9lh_path = "/arm9loaderhax.bin" --max length 38 characters including the first slash. if bigger, the path inside the .bin wont be changed
local backup_path = a9lh_path..".bak"

function unicodify(str)
    local new_str = ""
    for i = 1, #str,1 do
        new_str = new_str..string.sub(str,i,i)..string.char(00)
    end
    return new_str
end

function path_changer()
    local file = io.open(a9lh_path, FREAD)
    local a9lh_data = io.read(file, 0, io.size(file))
    io.close(file)
    local offset = string.find(a9lh_data, "%"..unicodify("arm9loaderhax.bin"))
    local new_path = unicodify(string.sub(a9lh_path,2,-1))
    if #new_path < 74 then
        for i = 1,74-#new_path,1 do
            new_path = new_path..string.char(00)
        end
        local file = io.open(a9lh_path, FWRITE)
        io.write(file, offset-1, new_path, 74)
        io.close(file)
    end
end

function main()
    Screen.refresh()
    Screen.debugPrint(5,5, "Welcome to the Luma3DS updater!", white, TOP_SCREEN)
    Screen.debugPrint(5,20, "Press A to update Luma3DS", white, TOP_SCREEN)
    Screen.debugPrint(5,35, "Press B to restore a Luma3DS backup", white, TOP_SCREEN)
    Screen.debugPrint(5,50, "Press START to go back to HBL/Home menu", white, TOP_SCREEN)
    Screen.debugPrint(5,155, "Thanks to:", white, TOP_SCREEN)
    Screen.debugPrint(5,170, "astronautlevel2 for the builds", white, TOP_SCREEN)
    Screen.debugPrint(5,185, "AuroraWright for her amazing CFW", white, TOP_SCREEN)
    Screen.debugPrint(5,200, "Rinnegatamante for lpp-3ds", white, TOP_SCREEN)
    Screen.debugPrint(5,215, "Hamcha for the idea", white, TOP_SCREEN)
    Screen.waitVblankStart()
    Screen.flip()
    while true do
        pad = Controls.read()
        if pad ~= oldPad then
            oldPad = pad
            if Controls.check(pad,KEY_START) then
                Screen.waitVblankStart()
                Screen.flip()
                System.exit()
            elseif Controls.check(pad,KEY_A) then
                Screen.refresh()
                Screen.clear(TOP_SCREEN)
                Screen.waitVblankStart()
                Screen.flip()
                if Network.isWifiEnabled() then
                    Screen.debugPrint(5,5, "Downloading latest.zip...", white, TOP_SCREEN)
                    Network.downloadFile(url, zip_path)
                    Screen.debugPrint(5,20, "File downloaded!", white, TOP_SCREEN)
                    Screen.debugPrint(5,35, "Backing up arm9loaderhax.bin...", white, TOP_SCREEN)
                    System.renameFile(a9lh_path, backup_path)
                    Screen.debugPrint(5,50, "Extracting arm9loaderhax.bin from latest.zip", white, TOP_SCREEN)
                    System.extractFromZIP(zip_path, "out/arm9loaderhax.bin", a9lh_path)
                    Screen.debugPrint(5,65, "Deleting latest.zip...", white, TOP_SCREEN)
                    System.deleteFile(zip_path)
                    Screen.debugPrint(5,80, "Changing path for reboot patch", white, TOP_SCREEN)
                    path_changer()
                    Screen.debugPrint(5,95, "Done!", white, TOP_SCREEN)
                    Screen.debugPrint(5,110, "Press START to go back to HBL/Home menu", white, TOP_SCREEN)
                    while true do
                        pad = Controls.read()
                        if pad ~= oldPad then
                            oldPad = pad
                            if Controls.check(pad,KEY_START) then
                                Screen.waitVblankStart()
                                Screen.flip()
                                System.exit()
                            end
                        end
                    end
                else
                    Screen.debugPrint(5,5, "WiFi is off! Please turn it on and retry!", white, TOP_SCREEN)
                    Screen.debugPrint(5,20, "Press START to go back to HBL/Home menu", white, TOP_SCREEN)
                    while true do
                        pad = Controls.read()
                        if pad ~= oldPad then
                            oldPad = pad
                            if Controls.check(pad,KEY_START) then
                                Screen.waitVblankStart()
                                Screen.flip()
                                System.exit()
                            end
                        end
                    end
                end
            elseif Controls.check(pad,KEY_B) then
                Screen.refresh()
                Screen.clear(TOP_SCREEN)
                Screen.waitVblankStart()
                Screen.flip()
                if System.doesFileExist(backup_path) then
                    Screen.debugPrint(5,5, "Deleting new arm9loaderhax.bin...", white, TOP_SCREEN)
                    System.deleteFile(a9lh_path)
                    Screen.debugPrint(5,20, "Renaming backup to arm9loaderhax.bin...", white, TOP_SCREEN)
                    System.renameFile(backup_path, a9lh_path)
                    Screen.debugPrint(5,35, "Press START to go back to HBL/Home menu", white, TOP_SCREEN)
                    while true do
                        pad = Controls.read()
                        if pad ~= oldPad then
                            oldPad = pad
                            if Controls.check(pad,KEY_START) then
                                Screen.waitVblankStart()
                                Screen.flip()
                                System.exit()
                            end
                        end
                    end
                else
                    Screen.debugPrint(5,5, "You don't have a backup to restore", white, TOP_SCREEN)
                    Screen.debugPrint(5,20, "Press START to go back to HBL/Home menu", white, TOP_SCREEN)
                    while true do
                        pad = Controls.read()
                        if pad ~= oldPad then
                            oldPad = pad
                            if Controls.check(pad,KEY_START) then
                                Screen.waitVblankStart()
                                Screen.flip()
                                System.exit()
                            end
                        end
                    end
                end
            end
        end
    end
end

main()