Glitches
Glitches can be found in Telefang games, especially in the bootleg versions. For a mostly complete list of glitches in the bootleg, visit Pokémon Diamond and Jade.
In Telefang 1
Manner Mode music glitch
This is a minor glitch that prevents the music from changing from one acre to another.
Steps to perform this glitch:
- First, one must turn "Manner Mode" on.
- Next, the player should wait for the phone to ring. It does not matter whether the phone is answered or not.
- After this, the music will not change at all from one acre to another. For example, the music will not change when going to Iris to Palm Sea. The only way to end this glitch is to enter a building or cave.
- If one were to battle, view the map, or go to the menu, the music will update to the location that the player is in after exiting one of these screens. For example, if one did this glitch in Iris, went to Palm Sea and battled, the music will be Palm Sea's music after the battle, which is what it should be. However, this glitch will still persist (for example, going back to Iris will not change it).
Personality glitches
Glitches that involve the Denjuu's personality.
Force a Denjuu to misbehave
This glitch forces Denjuu with specific personalities to misbehave.
- One should get a Denjuu with either a
Irritable personality (おこりんぼ), a 
Hotheaded personality (ちょーおこりんぼ) (both of which cause the Denjuu to sometimes use the first move automatically), a 
Stubborn personality (わがまま), or a 
Selfish personality (ちょーわがまま) (both of which cause the Denjuu to sometimes not attack at all). - The player should select "Fight."
- Next, the player should press B to return to the Fight/Flee screen. Each time this is done, there is a chance that the Denjuu will attack on its own (if it has a Irritable/ Hotheaded personality) or not attack at all (if it has a Stubborn/ Selfish personality).
- If this doesn't happen, then the player should repeat the above two steps until it does.
This occurs because every time the Fight/Flee screen is shown, there is a random chance that these four personalities will cause the Denjuu to use whatever move it wants/not attack at all.
Personality probability bug
Due to a glitch, a Denjuu is more likely to have a 
Relaxed (のんびり) personality than any other personality. There is a 14% chance of having a Relaxed personality and an 8% chance of having any other personality. This is because the game uses a random 8-bit number (0-255) for generating random events. However, the problem here is that if the random number comes up between 240 to 255, the Denjuu will have the "default" Relaxed personality, because the programmers only considered the outcomes from 0 to 240 (0-19 represents the first personality, Relaxed, 20-39 represents the second personality, 
Carefree, and so on).
Raise FD past 100
If a Denjuu calls the player and asks a question, and the player answers it correctly, this will cause the Denjuu's FD to increase. However, it increases even if this would cause it to exceed 100. The FD cannot exceed 100 in any other circumstance, and this causes glitches depending on the personality.
Frequently misbehaving Denjuu
If a Denjuu with an FD greater than 100 (due to the above glitch) has the following personalities below, it can very frequently misbehave, depending on the FD and personality. Normally, FD is only intended to fall between 0-100, so an FD value above 100 can cause an integer overflow.
The following personalities use the following formula for behaving well: (FD*2+55)/256
Relaxed (のんびり)
Carefree (ちょーのんびり)
Careless (あわてもの)
Oblivious (ちょーあわてもの)
Timid (おくびょう)
Cowardly (ちょーおくびょう)- Irritable (おこりんぼ)
- Hotheaded (ちょーおこりんぼ)
Due to integer overflow, the formula is effectively (FD*2-201)/256 when 100 < FD <= 228, and (FD*2-457)/256 when FD > 228.
For example, if a Denjuu's FD is 101, this results in a 1/256 chance of behaving well, meaning a 255/256 chance of either arriving late (Relaxed, Carefree, Careless, or Oblivious), running away (Timid or Cowardly), or using the first move (Irritable or Hotheaded).
By comparison, if a Denjuu has an FD of 0, it has a 55/256 chance of behaving well, meaning a 201/256 chance of misbehaving. If a Denjuu has an FD of 100, it has a 255/256 chance of behaving well, meaning a only a 1/256 chance of misbehaving.
The following personalities use the following formula for behaving well: (FD+155)/256
- Selfish (わがまま)
- Stubborn (ちょーわがまま)
Due to integer overflow, the formula is effectively (FD-101/256) when FD > 100.
For example, if a Denjuu's FD is 101, it has a 0/256 chance of behaving well, meaning that a Selfish or Stubborn Denjuu will never attack.
By comparison, if a Denjuu has an FD of 0, it has a 155/256 chance of attacking. If it has an FD of 100, it will always attack.
Denjuu with 
Honest (りちぎ) and 
Righteous (ちょーりちぎ) personalities are unaffected by the glitch due to lacking negative traits.
Field Guide completion glitch
If the Field Guide is completed when playing on a monochrome Game Boy, the graphics are garbled when the game attempts to congratulate the player. This is because the game does not check if it is being played on a monochrome Game Boy or not, so it tries to set attributes (i.e. color palettes of each tile) by writing to a RAM bank that does not exist on the original Game Boy, and ends up overwriting the tile map instead. [1]
99 items glitch
They player can only carry 99 of any item. However, when attempting to buy a 100th item, the shop will charge for it, even though the player cannot add it to their inventory, wasting money in the process. This bug was fixed in Telefang 2; shops will not sell an item that the player cannot carry more of.
Eryngo sprite error in Toulipa Antenna Tree
In a certain acre in Toulipa Antenna Tree (1F), there is a Gaiurus in Power Version and an Eryngo in Speed Version. However, in both versions, this Denjuu has a Byakubu sprite in the overworld, even though it should be an Eryngo sprite in Speed Version.
-
This Eryngo looks like a Gaiurus...
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...But when fighting him, it turns out to be an Eryngo in Speed Version.
VS battle disconnect graphical glitch
In a VS battle, if one player selected up to 3 Denjuu and is asked to confirm, and the other player resets the game by pressing A+B+Select+Start, the player that selected his or her Denjuu will see a minor graphical glitch when he is disconnected. The cursor sprite that is used to confirm or cancel the Denjuu selection remains even when the player is informed that he/she is disconnected.
Shop text glitch
If Shigeki stands in a specific spot in a shop, vertically, and buys an item, the text box on the top-left has glitches and shows part of the text in the bottom text box.
Overworld lag
When the phone rings in the overworld, if the player answers it on a specific frame, the game can lag, causing unintended effects, such as NPCs disappearing, and can even lead to arbitrary code execution. This can happen because normally, when either opening the map with Start, entering a building, or triggering a Telefang battle, the game writes temporarily bytes for sprites (including Shigeki and NPCs) from main RAM to SRAM, which are later written back to main RAM when a battle ends or the map is closed. Lag can prevent all of the bytes being written before an interrupt occurs. This glitch can be abused in speedruns, including a tool-assisted speedrun that beats the game in just over 5 minutes. [2]
(TODO: Elaborate on the details more, including how the arbitrary code execution works.)