Create a new version of paste:

-- this outputs some information related to the map loading procedure when the screen scrolls,
-- hopefully helpful for researching and recreating the scroll bug 
-- script by mugg ; with help from ais523, Sand

local PRINT_INFO = false

console.clear()
memory.usememorydomain("System Bus")

local cycles_at_frame_start = emu.totalexecutedcycles()
local cycles_at_frame_end = emu.totalexecutedcycles()
local print_after_this_frame = emu.framecount() + 1
local game_version = "-"
local t = ""
local t_frame_info = ""
local frames_processed = 0

-- these have to happen in the same frame
local requirement1 = false -- timer interrupt happens while ffea is 0x01
local requirement2 = false -- ffea gets set to 0x03

local bugframe_tbl = {}
local double_timer_interrupt_tbl = {}
local timer_interrupts_same_frame = 0

if gameinfo.getromhash() == "3A4DDB39B234A67FFB361EE7ABC3D23E0A8B1C89" then
	game_version = "1.0"
elseif gameinfo.getromhash() == "418203621B887CAA090215D97E3F509B79AFFD3E" then
	game_version = "1.1"
else
	print("This script will work only with GB Super Mario Land v1.0 or v1.1.")
	return
end

function text(x, y, text, color, backcolor)
	gui.pixelText(x, y, text, color, backcolor)
end

event.onframestart(function()
	cycles_at_frame_start = emu.totalexecutedcycles()
	
	if emu.framecount() > print_after_this_frame then
		local prefix = ""
		if frames_processed > 1 then 
			prefix = "\n"
		end
		t_frame_info = prefix .. "   FRAME " .. emu.framecount() + 1
	end
end)

event.onframeend(function()

	if emu.framecount()-1 > print_after_this_frame then
		t_frame_info = t_frame_info .. "  Cy:" .. emu.totalexecutedcycles() - cycles_at_frame_end
	end
	
	if emu.islagged() 
	and emu.framecount()-1 > print_after_this_frame then
		t_frame_info = t_frame_info .. "  **LAG**"
	end
		
	cycles_at_frame_end = emu.totalexecutedcycles()

	-- only print if the string isn't empty
	if PRINT_INFO then
		if #t_frame_info > 0 and #t > 0 then
			print(t_frame_info .. "\n" .. t)
		elseif #t_frame_info > 0 then
			print(t_frame_info)
		end
	end
	
	-- bugframe happened, save framecount and pixel pos
	if requirement1 and requirement2 then
		print("Bug frame!!!")
		local bugframe_info = {emu.framecount(), memory.read_u8(0xFFE9)*8}
		table.insert(bugframe_tbl, bugframe_info)
	end
	
	-- reset values
	requirement1 = false
	requirement2 = false
	t = ""
	t_frame_info = ""
	timer_interrupts_same_frame = 0

	frames_processed = frames_processed + 1
end)

tastudio.onbranchload(function()
	print_after_this_frame = emu.framecount() + 1
	frames_processed = -1
	console.clear()
	bugframe_tbl = {}
	double_timer_interrupt_tbl = {}
end)

event.onloadstate(function()
	print_after_this_frame = emu.framecount() + 1
	frames_processed = -1
	console.clear()
	bugframe_tbl = {}
	double_timer_interrupt_tbl = {}
end)

-- Write to $FFEA
-- passed val is always 0, it seems, hinting that this hook is not fully implemented
event.on_bus_write(function(addr, val, flags)
	if emu.framecount() > print_after_this_frame then
		local raw_val = memory.read_u8(0xFFEA)
		local val = string.upper(string.format("%02x",raw_val))
		local myname = "Write $FFEA (" .. val .. ")"
		t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
		
		if raw_val == 0x03 then
			requirement2 = true
		end
	end
end, 0xFFEA)

-- Write to $FFE9
event.on_bus_write(function(addr, val, flags)
	if emu.framecount() > print_after_this_frame then
		local val = string.upper(string.format("%02x",memory.read_u8(0xFFE9)))
		local myname = "Write $FFE9 (" .. val .. ")"
		t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
	end
end, 0xFFE9)

-- Exec $0040
event.on_bus_exec(function(addr, val, flags)
	if emu.framecount() > print_after_this_frame then
		local myname = "Execu $0040 (VBLANK INTERRUPT)"
		t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
	end
end, 0x0040)

-- Exec $0050
event.on_bus_exec(function(addr, val, flags)
	if emu.framecount() > print_after_this_frame then
		local myname = "Execu $0050 (TIMER INTERRUPT)"
		t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
		
		local ffea = memory.read_u8(0xFFEA)
		if ffea == 0x01 then 
			requirement1 = true
		end
		
		timer_interrupts_same_frame = timer_interrupts_same_frame + 1
		if timer_interrupts_same_frame >= 2 then
			t = t .. "\nTwo Timer Interrupts!"
			table.insert(double_timer_interrupt_tbl, emu.framecount()+1)
		end
	end
end, 0x0050)

-- Exec $0060
--[[
event.on_bus_exec(function(addr, val, flags)
	if emu.framecount() > print_after_this_frame then
		local myname = "Execu $0060 (JOYPAD INTERRUPT)"
		t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
	end
end, 0x0060)
--]]

-- game version dependent execs
if game_version == "1.0" then

	event.on_bus_exec(function(addr, val, flags)
		if emu.framecount() > print_after_this_frame then
			local myname = "Execu $2258 (READ $FFEA)"
			t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
		end
	end, 0x224F)
	
	event.on_bus_exec(function(addr, val, flags)
		if emu.framecount() > print_after_this_frame then
			local myname = "Execu $2254 (READ $FFE9)"
			t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
		end
	end, 0x2254)

elseif game_version == "1.1" then

	event.on_bus_exec(function(addr, val, flags)
		if emu.framecount() > print_after_this_frame then
			local myname = "Execu $2258 (READ $FFEA)"
			t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
		end
	end, 0x2258)
	
	event.on_bus_exec(function(addr, val, flags)
		if emu.framecount() > print_after_this_frame then
		
			local myname = "Execu $225D (READ $FFE9)"
			t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
		end
	end, 0x225D)

end

while true do
	
	gui.clearGraphics()
	
	if #bugframe_tbl > 0 then
		for i=1, #bugframe_tbl, 1 do
			local bugframe_entry = bugframe_tbl[i]
			
			if bugframe_entry ~= nil then
			
				local bugframe_framecount = bugframe_entry[1]
				local bugframe_pixel = bugframe_entry[2]
				local current_pixel = memory.read_u8(0xFFE9) * 8
				local display_pixel = (bugframe_pixel - current_pixel) - memory.read_u8(0xFF43)%8 + 216

				text(10, 10 + i*8, "bug Frame " .. bugframe_framecount, 0xFF00FF00, 0x80000000)
			
				if display_pixel > 160 then
					text(136,10 + i*8, "--->", 0xFFFF0000, 0x80000000)
				else
					gui.drawLine(display_pixel, 17, display_pixel, 144, 0xFFFF0000)
				end
				
				if display_pixel < 0 then
					bugframe_tbl[i] = nil
				end
				
			end
		end
	end
	
	--[[
	if #double_timer_interrupt_tbl > 0 then
		for j=1, #double_timer_interrupt_tbl, 1 do
			local frame = double_timer_interrupt_tbl[j]
			text(10, 80 + j*8, "two timer interrupts frame " .. frame, 0xFF00FF00, 0x80000000)
		end
	end
	--]]

	emu.frameadvance()
end