[Lua][Noob] Help With Code: A Simple Getflint Program.

Hi! For practice, I am writing a GetFlint program. I know, there are plenty of them around, this is just made to test skills and to learn a bit more. Here's my current code:

while true do
  if turtle.detect() == true then
   turtle.dig()
   turtle.place()
  elseif
   turtle.place() == false then
   turtle.dropUp()
   turtle.select(2)
   turtle.dropUp()
   turtle.select(3)
   turtle.dropUp()
   turtle.select(4)
   turtle.dropUp()
   turtle.select(1)
   print "No gravel detected, shutting down..."
   sleep(3)
   os.reboot()
end
end

The issue with this is: If I place gravel in the second slot of the turtle, it'll place the gravel in the chest that's on top of it, where only flint was supposed to go. How would I go about fixing this?

This part:

turtle.dropUp()
   turtle.select(2)
   turtle.place()
   turtle.dropUp()
   turtle.select(3)
   turtle.dropUp()
   turtle.select(4)
   turtle.dropUp()
   turtle.select(1)

Any way to make it shorter and do that to all the slots easily and in a cleaner way?

I know there are more issues, but I'll edit them later on, gotta go to sleep now.

Thanks in advance for your help!

Why don't you dedicate more slots to gravel? And when you want it to dump use
slot = 4
for i = 4, 8 do
turtle.select(slot)
turtle.dropUp()
slot = slot + 1
end

It's a lot neater

Well by dropping up, you are adding whatever is in your current slot, may i suggest using something like:

turtle.select(1)
while turtle.detect() do
	turtle.place()
	turtle.dig()
	for i=1,3 do
		if turtle.getItemCount(i) == 0 then
			break
		else
			turtle.select(i)
		end
	end
end
while not turtle.detect() do
	for i=4,8 do --This can be adjusted for however many slots you have reserved for gravel and flint. Here I have 1 slot set for gravel. Thus only 4-8 can have flint.
		if turtle.getItemCount(i)>0 then
			turtle.placeUp()
		end
	end
end