Important:

CurseForge axed support for versions < 1.5, so 1.2.5 packs won’t work with the CurseForge launcher anymore.
You’ll have to install a third-party launcher (e.g. ATLauncher) and use that one’s import feature.
(For ATLauncher: Instances – Import (upper left corner) – Browse – Select the zip file you downloaded manually from here – Click import.)

Due to uploading restrictions, the main file you get is the MP pack.

You can click on ‘‘Download Server pack” to get the server.

To get the SP version:

If you are in the CurseForge Client, click the three dots and choose “View Modpack website”
Open tab “Files”
Scroll down, download the SP version under “Additional files”
Import the zip file to your launcher of choice via “Create Custom Profile”

Versions:

Singleplayer (SP)
Multiplayer compatible (MP)
Bukkit server (Server)

Description:

This is a full-on retro pack in Minecraft version 1.2.5, containing everything you know from far back then—and a bit of convenience from the modern age:
Rush through everything and get ultra-op with Equivalent Exchange 2 (it's as unbalanced as ever =P) and make a big logistics system finally using Logistics Pipes again—before it got “energized”.
Build a massive frame quarry machine or complex sorting systems with Buildcraft and Redpower and protect yourself from enemies using MFFS. Also don’t forget Forestry with it's farms—and it’s bees, if you are into this kind of … work.
And if you use the singleplayer version, you can even experience the first “real” Thaumcraft, make Forestry almost obsolete with Minefactory Reloaded and build up your own (actually useful) village with Millénaire.
Do what you liked doing back then, while still being able to use your mouse properly thanks to MouseTweaks, sprint without excessive W-usage with KeySprint and remember what all the blocks were ’cause of Block Helper.

So yeah, the multiplayer version is missing a few mods I couldn’t find or don’t exist for Bukkit and has a few older versions of mods for the same reason.

There is also a complete server provided that has a few plugins pre-installed, additionally.

Videos:

I made a GERMAN Server Play series with a few friends playing this pack if you’d like to see the pack in action.

Disclaimer:

I left out some mods I have both versions of from the MP pack because of balancing reasons and personal preference, e.g. PowerConverters.
If you want to add further mods you can PM me here or on Discord and I’ll send you a link to my archive.

Also, of course I didn’t make any of these mods, all credit goes to the original authors listed next to the mod name (if known).
I just scraped these together from different sources, configured the IDs and changed versions around so everything is compatible.

Still, if you want to donate something there’s a button in the top right corner, but don’t feel pressured in any way. Thanks 🙂

MP-Modlist:

MinecraftForge by LexManos
Additional Pipes by tcooc
Advanced Machines by AtomicStryker
Advanced Solar Panels by SeNtiMeL
ArmorStatusHUD by bspkrs
Block Helper by ThexXTURBOXx
Buildcraft by SpaceToad
ChargingBench by [unknown]
ChickenChunks by ChickenBones
CodeChickenCore by ChickenBones
CompactSolars by cpw
DimensionalAnchors by immibis
EnderStorage by ChickenBones
Equivalent Exchange 2 by Pahimar
Font Fixer by Hyper Speeed
Forestry by SirSengir
Forestry IC² crops by [unknown]
GraviSuite by SeNtiMeL
ImmibisCore by immibis
Inventory Tweaks by Kobata
IronChests by cpw
IndustrialCraft 2 by IC²-Team
KeySprint by Tekens
LogisticsPipes by theZorro266
Lumy Skin Patch by lumy79
MFFS by darkguardsman
MouseTweaks by YaLTeR97
Mystcraft by XCompWiz
NEI Patch by [unknown]
NEI Buildcraft Plugin by mistaqur
NEI Forestry Plugin by mistaqur
NEI RailCraft Plugin by mistaqur
NEI RedPower Plugin by ChickenBones
NotEnoughItems by ChickenBones
Nuclear Control by Shedar
Portal Gun by iChun
Railcraft by CovertJaguar
Rei's Minimap by ReiFNSK
Redpower by Eloraam
Shelf by [unknown]
Single Player Commands by simo_415
StatusEffectHUD by bspkrs
Tubestuff by immibis
Wireless Redstone - ChickenBones Edition by ChickenBones

SP-Additions:

ArmorStand by [unknown]
Additional Buildcraft Objects by Flow86
Doggy Talents by RaustBlackDragon
EE Addon RP2 by [unknown]
EE Addon TC2 by [unknown]
Factorization by neptunepink
Greg's Lighting by Greg_Ewing
Laser Mod by Pigbear
Millénaire by Kinniken
Minefactory Reloaded by powercrystals
NEI IC2 Plugin by mistaqur
NEI Thaumcraft Plugin by mistaqur
NEI Thermal Expansion Plugin by mistaqur
PowerConverters by PowerCrystals
SecretDoor by [unknown]
Sneaky Pipes by Krapht
Somnia by MALfunction84
SparrowAPI by RaustBlackDragon
Steve's Carts by Vswe
Thaumcraft 2 by azanor
Thermal Expansion by KingLemmingCoFH, Cynycal
Vis Bees by Punknium

If you want to play with the Zeppelin mod:

Download the full version of Zeppelin mod from MCArchive.
Extract the wu.class-file from the mod and put it in the minecraft.jar / zip it on its own and put it in jarmods, separately.
Then remove the Wireless Redstone CBE mod (otherwise it’ll crash).

Full Retro