Daiku no Gen San (full title "Daiku no Gen-san - Kachikachi no Tonkachi ga Kachi") is a Japanese Only GBC game, from the series know outside Japan as Hammerin' Harry. It's a mix of Platformer and Puzzle, overall, a very fun little game (and has an english translation). But it has one weird and widely seen issue.
On Stage 1-4, in one of the sections where you need to use an elevator to solve a puzzle by transporting a block on the elevator to reach a switch, the game ALWAYS hangs up in the middle of this event. Thing is, pretty much every emulator has this problem, except Visual Boy Advance on PC. I tried in BGB, I tried on Gambatte and a few others on different platforms, mGBA included (tried many versions, including last stable version and nightly). In all of those, the game hangs right in that instant. I really do not know why, I tried all the different dumps I found, it always happens, once the elevator (with the block on it) reaches one specific point vertically, the game stops and the music also gets somewhat corrupted, as if it is missing channels.
I attached a Zip File containing a SRAM file (which should let you continue on the specific room that this happens) and two save states, one before it happens (Save State 3), and one where the freeze already happened (Save State 4). You only need to touch the switch (that thing with a face on the right) and go back to the red and white platform.
Seems to happen in all versions of mGBA, the files are from the Wii release (although I also tried the PC release), so it's not a regression, and seeing how most other emulators also suffer from this, something very weird is going on.