Ok for this trophy you need to collect tool kits to be able to upgrade your weapons
Handy for this is finding shiv doors as they always have nice amounts of creation parts, by creation parts i don't mean the parts for making health kits etc. They are either small shiny cog like things or found in boxes with usually about 20 of them and those are the ones usually found in shiv doors and also safes.
This video shows you where all the shiv doors are (remember always keep a shiv handy for a door)
He mentions that this is glitched, well i actually came across what i believe is the real problem.
When i was in the library i decided to stop playing for that evening and saved the game just after opening a shiv door and Ellie telling me a joke. The next time i went to play i noticed something, the door was closed again! So be careful in areas if you decide to save in an area where you just unlocked a shiv door AND the same goes with jokes because i thought i should wait and see if the joke had been reset also which it had.
So i truly believe there is no actual glitch to worry about but instead the issues i just told you about, so keep that in mind when saving and loading games or you could get caught out.
Time stamps included
SHIV DOOR TIMELINE:
01. (Downtown) The Goldstone Building / 0:52
02. (Museum) The Concession Area / 1:21
03. (The Woods) Storage Area / 1:54
04. (The Woods) Back Ally of Marquis Music Store / 2:20
05. (Alone and Forsaken) Kingston Bookstore 2nd Floor / 2:55
06. (Alone and Forsaken) Just before The Hotel / 3:29
07. (Financial District) HS&L Credit Union / 3:50
08. (Escape the City) Right after meeting Henry & Sam / 4:18
09. (Hydroelectric Dam) Control Room / 4:49
10. (Science Building) Lecture Room 104 / 5:06
11. (Cabin Resort) Behind the Motel (Joel) / 5:37
12. (Underground Tunnel) Security Gate Area / 6:22
13. (Hospital) Floor 6 Reception Area / 7:14
This next video shows you where to find the tool kits needed.
Those cog like things you see Jole collect after the toolbox are the creation parts you need to be finding to be able to actually upgrade your weapons, they are a bit like the pills you need for the
Except you can't just open your back pack and upgrade your weapons, you need to find work benches which i am afraid to say i have not been able to find a guide showing you all the work benches or all creation parts either but not to worry! I have played this game numerous times and never have i finished either on my first playthrough. Both upgrades for this trophy and Everything we've been through carry over to New Game+ where you will get both trophies for sure!
And a video for all the safes, also usually full of creation parts and pills.
Also one more video showing you where all the weapons are found although sometimes you can find them in other areas also. Weapons like Axes and the Machete don't matter as they can't be upgraded.EDIT 24th/10/2014:
I managed to find us a text version of where the work benches are. Granted they could be a little bit better described but it certainly is better than nothing and as i said you wont be getting this on your first play through so you should have an idea of where about the underlined areas are and when you are coming up to them. I also would like to add that it takes more parts to upgrade the weapons on the higher levels of difficulty so you really want to look as hard as you possibly can in every corner, drawer and cupboard you can open for all those parts you need and i can not stress how important those shiv doors and safes are for you getting this trophy by the 2nd play through, also an extra piece of advice is to keep your upgrade parts for the guns you get much later on in the game and upgrade them as far on as possible in to the game on your first play through, that way when you start new game+ you wont have to wait all the way in to the game to get the weapons because you will not start out with all the weapons on new game+. You collect them just like you did the first time round so they wont be available to upgrade until you collect them again. That's something to keep in mind but you need to play new game+ to open up the harder levels anyway so it's only if you want to get that trophy quicker for some reason.Outskirts
The first workbench will be on the bottom floor of the museum, just after escaping the infected through the garage door.Bill’s Town
Go to the Church basement.Pittsburgh
Inside the upper first building of the hunter’s camp.Pittsburgh
Near the office behind hotel restaurant’s kitchen.Pittsburgh
Located in the Financial District. Use the cart to climb over the vending machine.The Suburbs
Inside the opened garage door.Tommy’s Dam
Left side of the dam control roomThe University
Inside the depot.The University
Inside the Science lab, the workbench is located left from the entrance of the building.Bus Depot
Located in the Triage Area in the far tent.Bus Depot
After Ellie first lets you in, you’ll find the workbench in the first room of the Hospital Tunnel Ventilation System
The main video shows you the work benches we need to look out for. If you look at the top right you will see 1/5, that is the number of tool kits you have found.
Now look at the upgrades them selves, pause the video once he opens up the work bench screen.
You will see Pistol then number 1 with pliers next to it, that is the toolkit level required to be able to do the upgrade and to the right of that you see 75 with a cog image, those are the creation parts we have been looking for in shiv doors and not just shiv doors but look everywhere, shiv doors are just best for finding a large amount in one go, sometimes there are one or two scattered about the ground here and there. You can see just how many you have collected up at the top right where he has 107 in total.
If you start the video playing again you will see as he looks through the upgrades some are red like for the hunting rifle for example, you need to have 3 tool kits to upgrade the armour power even though you have the correct amount of parts to upgrade it.
I hope this will help you on upgrading your weapon and let you know not to worry if you don't get it first time round.